diff --git a/build/libaegisub/libaegisub.vcxproj b/build/libaegisub/libaegisub.vcxproj
index a778d8d15..7e3cd44c0 100644
--- a/build/libaegisub/libaegisub.vcxproj
+++ b/build/libaegisub/libaegisub.vcxproj
@@ -55,6 +55,8 @@
     <ClInclude Include="$(SrcDir)include\libaegisub\exception.h" />
     <ClInclude Include="$(SrcDir)include\libaegisub\file_mapping.h" />
     <ClInclude Include="$(SrcDir)include\libaegisub\format.h" />
+    <ClInclude Include="$(SrcDir)include\libaegisub\format_flyweight.h" />
+    <ClInclude Include="$(SrcDir)include\libaegisub\format_path.h" />
     <ClInclude Include="$(SrcDir)include\libaegisub\fs.h" />
     <ClInclude Include="$(SrcDir)include\libaegisub\fs_fwd.h" />
     <ClInclude Include="$(SrcDir)include\libaegisub\hotkey.h" />
diff --git a/build/libaegisub/libaegisub.vcxproj.filters b/build/libaegisub/libaegisub.vcxproj.filters
index 71d5059d4..474ac2553 100644
--- a/build/libaegisub/libaegisub.vcxproj.filters
+++ b/build/libaegisub/libaegisub.vcxproj.filters
@@ -173,6 +173,12 @@
     <ClInclude Include="$(SrcDir)include\libaegisub\format.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="$(SrcDir)include\libaegisub\format_flyweight.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="$(SrcDir)include\libaegisub\format_path.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="$(SrcDir)include\libaegisub\character_count.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/build/tests/tests.vcxproj b/build/tests/tests.vcxproj
index 7ab92bbb7..0cc0e1ab7 100644
--- a/build/tests/tests.vcxproj
+++ b/build/tests/tests.vcxproj
@@ -42,6 +42,7 @@
     <ClCompile Include="$(SrcDir)tests\cajun.cpp" />
     <ClCompile Include="$(SrcDir)tests\color.cpp" />
     <ClCompile Include="$(SrcDir)tests\dialogue_lexer.cpp" />
+    <ClCompile Include="$(SrcDir)tests\format.cpp" />
     <ClCompile Include="$(SrcDir)tests\fs.cpp" />
     <ClCompile Include="$(SrcDir)tests\hotkey.cpp" />
     <ClCompile Include="$(SrcDir)tests\iconv.cpp" />
diff --git a/libaegisub/include/libaegisub/format.h b/libaegisub/include/libaegisub/format.h
index bda534f2a..17781ae4c 100644
--- a/libaegisub/include/libaegisub/format.h
+++ b/libaegisub/include/libaegisub/format.h
@@ -14,11 +14,15 @@
 //
 // Aegisub Project http://www.aegisub.org/
 
+#include <libaegisub/fs_fwd.h>
+
 #include <boost/interprocess/streams/vectorstream.hpp>
 #include <boost/io/ios_state.hpp>
-#include <cassert>
+#include <codecvt>
 #include <type_traits>
 
+class wxString;
+
 namespace agi { namespace format_detail {
 // A static cast which throws at runtime if the cast is invalid rather than
 // failing to compile, as with format strings we don't know what type to cast
@@ -40,36 +44,75 @@ Out runtime_cast(In const& value) {
 	return runtime_cast_helper<In, Out>::cast(value);
 }
 
-template<typename T>
-void write_string(std::ostream& out, int, T const& value) {
-	out << value;
-}
-
 // Check length for string types
-inline void write_string(std::ostream& out, int max_len, const char *value) {
-	if (max_len <= 0)
-		out << value;
-	else {
-		std::streamsize len = 0;
-		for (; len < max_len && value[len]; ++len) ;
-		out.write(value, len);
-	}
+template<typename Char>
+int actual_len(int max_len, const Char *value) {
+	int len = 0;
+	while (value[len] && (max_len <= 0 || len < max_len)) ++len;
+	return len;
 }
 
-inline void write_string(std::ostream& out, int max_len, std::string const& value) {
+template<typename Char>
+int actual_len(int max_len, std::basic_string<Char> value) {
 	if (max_len > 0 && static_cast<size_t>(max_len) < value.size())
-		out.write(value.data(), max_len);
-	else
-		out << value;
+		return max_len;
+	return value.size();
 }
 
+template<typename Char>
+inline void do_write_str(std::basic_ostream<Char>& out, const Char *str, int len) {
+	out.write(str, len);
+}
+
+inline void do_write_str(std::ostream& out, const wchar_t *str, int len) {
+	std::wstring_convert<std::codecvt_utf8<wchar_t>> utf8_conv;
+	auto u8 = utf8_conv.to_bytes(str, str + len);
+	out.write(u8.data(), u8.size());
+}
+
+inline void do_write_str(std::wostream& out, const char *str, int len) {
+	std::wstring_convert<std::codecvt_utf8<wchar_t>> utf8_conv;
+	auto wc = utf8_conv.from_bytes(str, str + len);
+	out.write(wc.data(), wc.size());
+}
+}
+
+template<typename Char, typename T>
+struct writer {
+	static void write(std::basic_ostream<Char>& out, int, T const& value) {
+		out << value;
+	}
+};
+
+// Ensure things with specializations don't get implicitly initialized
+template<> struct writer<char, agi::fs::path>;
+template<> struct writer<wchar_t, agi::fs::path>;
+template<> struct writer<char, wxString>;
+template<> struct writer<wchar_t, wxString>;
+
+template<typename StreamChar, typename Char>
+struct writer<StreamChar, const Char *> {
+	static void write(std::basic_ostream<StreamChar>& out, int max_len, const Char *value) {
+		format_detail::do_write_str(out, value, format_detail::actual_len(max_len, value));
+	}
+};
+
+template<typename StreamChar, typename Char>
+struct writer<StreamChar, std::basic_string<Char>> {
+	static void write(std::basic_ostream<StreamChar>& out, int max_len, std::basic_string<Char> const& value) {
+		format_detail::do_write_str(out, value.data(), format_detail::actual_len(max_len, value));
+	}
+};
+
+namespace format_detail {
+template<typename Char>
 class formatter {
 	formatter(const formatter&) = delete;
 	formatter& operator=(const formatter&) = delete;
 
-	std::ostream& out;
-	const char *fmt;
-	const char *fmt_cur = nullptr;
+	std::basic_ostream<Char>& out;
+	const Char *fmt;
+	const Char *fmt_cur = nullptr;
 
 	bool read_width = false;
 	bool read_precision = false;
@@ -78,7 +121,7 @@ class formatter {
 	int width = 0;
 	int precision = 0;
 
-	boost::io::ios_all_saver saver;
+	boost::io::basic_ios_all_saver<Char> saver;
 
 	void read_and_append_up_to_next_specifier() {
 		for (std::streamsize len = 0; ; ++len) {
@@ -168,7 +211,7 @@ class formatter {
 
 	void parse_length_modifiers() {
 		// Where "parse" means "skip" since we don't need them
-		for (char c = *fmt_cur;
+		for (Char c = *fmt_cur;
 			c == 'l' || c == 'h' || c == 'L' || c == 'j' || c == 'z' || c == 't';
 			c = *++fmt_cur);
 	}
@@ -198,7 +241,7 @@ class formatter {
 	}
 
 public:
-	formatter(std::ostream& out, const char *fmt) : out(out), fmt(fmt), saver(out) { }
+	formatter(std::basic_ostream<Char>& out, const Char *fmt) : out(out), fmt(fmt), saver(out) { }
 	~formatter() {
 		// Write remaining formatting string
 		for (std::streamsize len = 0; ; ++len) {
@@ -245,7 +288,7 @@ public:
 		out.width(width);
 		out.precision(precision < 0 ? 6 : precision);
 
-		char c = *fmt_cur ? fmt_cur[0] : 's';
+		Char c = *fmt_cur ? fmt_cur[0] : 's';
 		if (c >= 'A' && c <= 'Z') {
 			out.setf(std::ios::uppercase);
 			c += 'a' - 'A';
@@ -254,7 +297,7 @@ public:
 		switch (c) {
 		case 'c':
 			out.setf(std::ios::dec, std::ios::basefield);
-			out << runtime_cast<char>(value);
+			out << runtime_cast<Char>(value);
 			break;
 		case 'd': case 'i':
 			out.setf(std::ios::dec, std::ios::basefield);
@@ -292,7 +335,7 @@ public:
 			break;
 		default: // s and other
 			out.setf(std::ios::boolalpha);
-			write_string(out, precision, value);
+			writer<Char, typename std::decay<T>::type>::write(out, precision, value);
 			break;
 		}
 
@@ -301,23 +344,24 @@ public:
 };
 
 // Base case for variadic template recursion
-inline void format(formatter&&) { }
+template<typename Char>
+inline void format(formatter<Char>&&) { }
 
-template<typename T, typename... Args>
-void format(formatter&& fmt, T&& first, Args&&... rest) {
+template<typename Char, typename T, typename... Args>
+void format(formatter<Char>&& fmt, T&& first, Args&&... rest) {
 	fmt(first);
 	format(std::move(fmt), std::forward<Args>(rest)...);
 }
 } // namespace format_detail
 
-template<typename... Args>
-void format(std::ostream& out, const char *fmt, Args&&... args) {
-	format(format_detail::formatter(out, fmt), std::forward<Args>(args)...);
+template<typename Char, typename... Args>
+void format(std::basic_ostream<Char>& out, const Char *fmt, Args&&... args) {
+	format(format_detail::formatter<Char>(out, fmt), std::forward<Args>(args)...);
 }
 
-template<typename... Args>
-std::string format(const char *fmt, Args&&... args) {
-	boost::interprocess::basic_vectorstream<std::string> out;
+template<typename Char, typename... Args>
+std::basic_string<Char> format(const Char *fmt, Args&&... args) {
+	boost::interprocess::basic_vectorstream<std::basic_string<Char>> out;
 	format(out, fmt, std::forward<Args>(args)...);
 	return out.vector();
 }
diff --git a/libaegisub/include/libaegisub/format_flyweight.h b/libaegisub/include/libaegisub/format_flyweight.h
new file mode 100644
index 000000000..aa0706127
--- /dev/null
+++ b/libaegisub/include/libaegisub/format_flyweight.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2014, Thomas Goyne <plorkyeran@aegisub.org>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+// Aegisub Project http://www.aegisub.org/
+
+#include <libaegisub/fs_fwd.h>
+
+#include <boost/flyweight.hpp>
+
+namespace agi {
+template<>
+struct writer<char, boost::flyweight<std::string>> {
+	static void write(std::basic_ostream<char>& out, int max_len, boost::flyweight<std::string> const& value) {
+		writer<char, std::string>::write(out, max_len, value.get());
+	}
+};
+
+template<>
+struct writer<wchar_t, boost::flyweight<std::string>> {
+	static void write(std::basic_ostream<wchar_t>& out, int max_len, boost::flyweight<std::string> const& value) {
+		writer<wchar_t, std::string>::write(out, max_len, value.get());
+	}
+};
+}
+
diff --git a/libaegisub/include/libaegisub/format_path.h b/libaegisub/include/libaegisub/format_path.h
new file mode 100644
index 000000000..ff195ece6
--- /dev/null
+++ b/libaegisub/include/libaegisub/format_path.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2014, Thomas Goyne <plorkyeran@aegisub.org>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+// Aegisub Project http://www.aegisub.org/
+
+#include <libaegisub/fs_fwd.h>
+
+#include <boost/filesystem/path.hpp>
+
+namespace agi {
+// Default version quotes the path
+template<>
+struct writer<char, agi::fs::path> {
+	static void write(std::basic_ostream<char>& out, int max_len, agi::fs::path const& value) {
+		out << value.string();
+	}
+};
+
+template<>
+struct writer<wchar_t, agi::fs::path> {
+	static void write(std::basic_ostream<wchar_t>& out, int max_len, agi::fs::path const& value) {
+		out << value.wstring();
+	}
+};
+}
diff --git a/po/make_pot.sh b/po/make_pot.sh
index 58e77b035..d19079ad7 100755
--- a/po/make_pot.sh
+++ b/po/make_pot.sh
@@ -13,7 +13,7 @@ maybe_append() {
 }
 
 find ../src ../src/command -name \*.cpp -o -name \*.h \
-  | xgettext --files-from=- -o - --c++ -k_ -kSTR_MENU -kSTR_DISP -kSTR_HELP -kwxT -kwxPLURAL:1,2 \
+  | xgettext --files-from=- -o - --c++ -k_ -kSTR_MENU -kSTR_DISP -kSTR_HELP -kfmt_tl -kfmt_plural:2,3 -kwxT -kwxPLURAL:1,2 \
   | sed 's/SOME DESCRIPTIVE TITLE./Aegisub 3.2/' \
   | sed 's/YEAR/2005-2014/' \
   | sed "s/THE PACKAGE'S COPYRIGHT HOLDER/Rodrigo Braz Monteiro, Niels Martin Hansen, Thomas Goyne et. al./" \
diff --git a/src/agi_pre.h b/src/agi_pre.h
index 89e2827ba..b31970552 100644
--- a/src/agi_pre.h
+++ b/src/agi_pre.h
@@ -72,6 +72,7 @@
 // Common C++
 #include <algorithm>
 #include <array>
+#include <codecvt>
 #include <functional>
 #include <iterator>
 #include <limits>
@@ -81,9 +82,10 @@
 #include <set>
 #include <string>
 #include <type_traits>
+#include <type_traits>
 #include <typeinfo>
-#include <utility>
 #include <unordered_map>
+#include <utility>
 #include <vector>
 
 #ifdef _MSC_VER
@@ -100,6 +102,7 @@
 // Boost
 #include <boost/container/list.hpp>
 #include <boost/flyweight.hpp>
+#include <boost/io/ios_state.hpp>
 #include <boost/range/adaptor/filtered.hpp>
 #include <boost/range/adaptor/transformed.hpp>
 #include <boost/range/algorithm.hpp>
@@ -109,6 +112,7 @@
 #include <boost/filesystem/path.hpp>
 #undef BOOST_NO_SCOPED_ENUMS
 #include <boost/interprocess/streams/bufferstream.hpp>
+#include <boost/interprocess/streams/vectorstream.hpp>
 
 // wxWidgets headers
 #include <wx/defs.h> // Leave this first.
diff --git a/src/audio_display.cpp b/src/audio_display.cpp
index 8f086dc75..5c9135143 100644
--- a/src/audio_display.cpp
+++ b/src/audio_display.cpp
@@ -37,6 +37,7 @@
 #include "audio_renderer_waveform.h"
 #include "audio_timing.h"
 #include "compat.h"
+#include "format.h"
 #include "include/aegisub/audio_provider.h"
 #include "include/aegisub/context.h"
 #include "include/aegisub/hotkey.h"
@@ -417,21 +418,21 @@ public:
 
 				if (changed_hour)
 				{
-					time_string = wxString::Format("%d:%02d:", mark_hour, mark_minute);
+					time_string = fmt_wx("%d:%02d:", mark_hour, mark_minute);
 					last_hour = mark_hour;
 					last_minute = mark_minute;
 				}
 				else if (changed_minute)
 				{
-					time_string = wxString::Format("%d:", mark_minute);
+					time_string = fmt_wx("%d:", mark_minute);
 					last_minute = mark_minute;
 				}
 				if (scale_minor >= Sc_Decisecond)
-					time_string += wxString::Format("%02d", (int)mark_second);
+					time_string += fmt_wx("%02d", mark_second);
 				else if (scale_minor == Sc_Centisecond)
-					time_string += wxString::Format("%02.1f", mark_second);
+					time_string += fmt_wx("%02.1f", mark_second);
 				else
-					time_string += wxString::Format("%02.2f", mark_second);
+					time_string += fmt_wx("%02.2f", mark_second);
 
 				int tw, th;
 				dc.GetTextExtent(time_string, &tw, &th);
@@ -673,7 +674,7 @@ wxString AudioDisplay::GetZoomLevelDescription(int level) const
 	const int base_pixels_per_second = 50; /// @todo Make this customisable along with the above
 	const int second_pixels = 100 * base_pixels_per_second / factor;
 
-	return wxString::Format(_("%d%%, %d pixel/second"), factor, second_pixels);
+	return fmt_tl("%d%%, %d pixel/second", factor, second_pixels);
 }
 
 int AudioDisplay::GetZoomLevelFactor(int level)
diff --git a/src/command/command.cpp b/src/command/command.cpp
index 2feaaf60e..edc041b6a 100644
--- a/src/command/command.cpp
+++ b/src/command/command.cpp
@@ -15,6 +15,7 @@
 #include "command.h"
 
 #include "../compat.h"
+#include "../format.h"
 
 #include <libaegisub/log.h>
 
@@ -27,7 +28,7 @@ namespace cmd {
 	static iterator find_command(std::string const& name) {
 		auto it = cmd_map.find(name);
 		if (it == cmd_map.end())
-			throw CommandNotFound(from_wx(wxString::Format(_("'%s' is not a valid command name"), to_wx(name))));
+			throw CommandNotFound(agi::format(_("'%s' is not a valid command name"), name));
 		return it;
 	}
 
diff --git a/src/command/edit.cpp b/src/command/edit.cpp
index 196cc79d3..f6a0a1e9e 100644
--- a/src/command/edit.cpp
+++ b/src/command/edit.cpp
@@ -38,6 +38,7 @@
 #include "../compat.h"
 #include "../dialog_search_replace.h"
 #include "../dialogs.h"
+#include "../format.h"
 #include "../include/aegisub/context.h"
 #include "../initial_line_state.h"
 #include "../libresrc/libresrc.h"
@@ -50,7 +51,6 @@
 #include "../video_controller.h"
 
 #include <libaegisub/address_of_adaptor.h>
-#include <libaegisub/format.h>
 #include <libaegisub/of_type_adaptor.h>
 #include <libaegisub/make_unique.h>
 
@@ -1146,12 +1146,12 @@ struct edit_redo final : public Command {
 	wxString StrMenu(const agi::Context *c) const override {
 		return c->subsController->IsRedoStackEmpty() ?
 			_("Nothing to &redo") :
-		wxString::Format(_("&Redo %s"), c->subsController->GetRedoDescription());
+			fmt_tl("&Redo %s", c->subsController->GetRedoDescription());
 	}
 	wxString StrDisplay(const agi::Context *c) const override {
 		return c->subsController->IsRedoStackEmpty() ?
 			_("Nothing to redo") :
-		wxString::Format(_("Redo %s"), c->subsController->GetRedoDescription());
+			fmt_tl("Redo %s", c->subsController->GetRedoDescription());
 	}
 
 	bool Validate(const agi::Context *c) override {
@@ -1172,12 +1172,12 @@ struct edit_undo final : public Command {
 	wxString StrMenu(const agi::Context *c) const override {
 		return c->subsController->IsUndoStackEmpty() ?
 			_("Nothing to &undo") :
-			wxString::Format(_("&Undo %s"), c->subsController->GetUndoDescription());
+			fmt_tl("&Undo %s", c->subsController->GetUndoDescription());
 	}
 	wxString StrDisplay(const agi::Context *c) const override {
 		return c->subsController->IsUndoStackEmpty() ?
 			_("Nothing to undo") :
-			wxString::Format(_("Undo %s"), c->subsController->GetUndoDescription());
+			fmt_tl("Undo %s", c->subsController->GetUndoDescription());
 	}
 
 	bool Validate(const agi::Context *c) override {
diff --git a/src/command/video.cpp b/src/command/video.cpp
index 115aa6c86..84dbb24e3 100644
--- a/src/command/video.cpp
+++ b/src/command/video.cpp
@@ -38,6 +38,7 @@
 #include "../dialog_detached_video.h"
 #include "../dialog_manager.h"
 #include "../dialogs.h"
+#include "../format.h"
 #include "../frame_main.h"
 #include "../include/aegisub/context.h"
 #include "../include/aegisub/subtitles_provider.h"
@@ -50,7 +51,6 @@
 #include "../video_display.h"
 #include "../video_frame.h"
 
-#include <libaegisub/format.h>
 #include <libaegisub/fs.h>
 #include <libaegisub/path.h>
 #include <libaegisub/make_unique.h>
@@ -232,7 +232,7 @@ struct video_cycle_subtitles_provider final : public cmd::Command {
 		if (it == end(providers)) it = begin(providers);
 
 		OPT_SET("Subtitle/Provider")->SetString(*it);
-		c->frame->StatusTimeout(wxString::Format(_("Subtitles provider set to %s"), to_wx(*it)), 5000);
+		c->frame->StatusTimeout(fmt_tl("Subtitles provider set to %s", *it), 5000);
 	}
 };
 
diff --git a/src/dialog_about.cpp b/src/dialog_about.cpp
index 75d51f0cf..d56de1148 100644
--- a/src/dialog_about.cpp
+++ b/src/dialog_about.cpp
@@ -28,6 +28,7 @@
 // Aegisub Project http://www.aegisub.org/
 
 #include "libresrc/libresrc.h"
+#include "format.h"
 #include "version.h"
 
 #include <wx/button.h>
@@ -126,7 +127,7 @@ struct AboutScreen : wxDialog {
 		aboutString += translatorCredit;
 		aboutString += "\n" + libString;
 		aboutString += _("\nSee the help file for full credits.\n");
-		aboutString += wxString::Format(_("Built by %s on %s."), GetAegisubBuildCredit(), GetAegisubBuildTime());
+		aboutString += fmt_tl("Built by %s on %s.", GetAegisubBuildCredit(), GetAegisubBuildTime());
 
 		// Replace copyright symbol
 		wxChar copySymbol = 0xA9;
diff --git a/src/dialog_automation.cpp b/src/dialog_automation.cpp
index 69ef63033..dd53db7b4 100644
--- a/src/dialog_automation.cpp
+++ b/src/dialog_automation.cpp
@@ -31,6 +31,7 @@
 #include "compat.h"
 #include "command/command.h"
 #include "dialog_manager.h"
+#include "format.h"
 #include "help_button.h"
 #include "include/aegisub/context.h"
 #include "libresrc/libresrc.h"
@@ -273,20 +274,20 @@ void DialogAutomation::OnInfo(wxCommandEvent &)
 	wxArrayString info;
 	std::back_insert_iterator<wxArrayString> append_info(info);
 
-	info.push_back(wxString::Format(
-		_("Total scripts loaded: %d\nGlobal scripts loaded: %d\nLocal scripts loaded: %d\n"),
-		(int)local_manager->GetScripts().size() + (int)global_manager->GetScripts().size(),
-		(int)global_manager->GetScripts().size(),
-		(int)local_manager->GetScripts().size()));
+	info.push_back(fmt_tl(
+		"Total scripts loaded: %d\nGlobal scripts loaded: %d\nLocal scripts loaded: %d\n",
+		local_manager->GetScripts().size() + global_manager->GetScripts().size(),
+		global_manager->GetScripts().size(),
+		local_manager->GetScripts().size()));
 
 	info.push_back(_("Scripting engines installed:"));
 	boost::transform(Automation4::ScriptFactory::GetFactories(), append_info,
 		[](std::unique_ptr<Automation4::ScriptFactory> const& f) {
-			return wxString::Format("- %s (%s)", to_wx(f->GetEngineName()), to_wx(f->GetFilenamePattern()));
+			return fmt_wx("- %s (%s)", f->GetEngineName(), f->GetFilenamePattern());
 		});
 
 	if (ei) {
-		info.push_back(wxString::Format(_("\nScript info:\nName: %s\nDescription: %s\nAuthor: %s\nVersion: %s\nFull path: %s\nState: %s\n\nFeatures provided by script:"),
+		info.push_back(fmt_tl("\nScript info:\nName: %s\nDescription: %s\nAuthor: %s\nVersion: %s\nFull path: %s\nState: %s\n\nFeatures provided by script:",
 			ei->script->GetName(),
 			ei->script->GetDescription(),
 			ei->script->GetAuthor(),
@@ -295,10 +296,10 @@ void DialogAutomation::OnInfo(wxCommandEvent &)
 			ei->script->GetLoadedState() ? _("Correctly loaded") : _("Failed to load")));
 
 		boost::transform(ei->script->GetMacros(), append_info, [=](const cmd::Command *f) {
-			return wxString::Format(_("    Macro: %s (%s)"), f->StrDisplay(context), to_wx(f->name()));
+			return fmt_tl("    Macro: %s (%s)", f->StrDisplay(context), f->name());
 		});
 		boost::transform(ei->script->GetFilters(), append_info, [](const Automation4::ExportFilter* f) {
-			return wxString::Format(_("    Export filter: %s"), to_wx(f->GetName()));
+			return fmt_tl("    Export filter: %s", f->GetName());
 		});
 	}
 
diff --git a/src/dialog_autosave.cpp b/src/dialog_autosave.cpp
index b06c94c0b..73981005f 100644
--- a/src/dialog_autosave.cpp
+++ b/src/dialog_autosave.cpp
@@ -15,6 +15,7 @@
 // Aegisub Project http://www.aegisub.org/
 
 #include "compat.h"
+#include "format.h"
 #include "libresrc/libresrc.h"
 #include "options.h"
 
@@ -140,7 +141,7 @@ void DialogAutosave::Populate(std::map<wxString, AutosaveFile> &files_map, std::
 		auto it = files_map.find(name);
 		if (it == files_map.end())
 			it = files_map.insert({name, AutosaveFile{name}}).first;
-		it->second.versions.push_back(Version{wxFileName(directory, fn).GetFullPath(), date, wxString::Format(name_fmt, date.Format())});
+		it->second.versions.push_back(Version{wxFileName(directory, fn).GetFullPath(), date, agi::wxformat(name_fmt, date.Format())});
 	} while (dir.GetNext(&fn));
 }
 
diff --git a/src/dialog_detached_video.cpp b/src/dialog_detached_video.cpp
index 727eca4fd..80995a8ca 100644
--- a/src/dialog_detached_video.cpp
+++ b/src/dialog_detached_video.cpp
@@ -34,6 +34,7 @@
 
 #include "dialog_detached_video.h"
 
+#include "format.h"
 #include "include/aegisub/context.h"
 #include "include/aegisub/hotkey.h"
 #include "options.h"
@@ -44,6 +45,7 @@
 #include "video_controller.h"
 #include "video_display.h"
 
+#include <libaegisub/format_path.h>
 #include <libaegisub/make_unique.h>
 
 #include <boost/filesystem/path.hpp>
@@ -61,7 +63,7 @@ DialogDetachedVideo::DialogDetachedVideo(agi::Context *context)
 	// Set obscure stuff
 	SetExtraStyle((GetExtraStyle() & ~wxWS_EX_BLOCK_EVENTS) | wxWS_EX_PROCESS_UI_UPDATES);
 
-	SetTitle(wxString::Format(_("Video: %s"), context->project->VideoName().filename().wstring()));
+	SetTitle(fmt_tl("Video: %s", context->project->VideoName().filename()));
 
 	old_display->Unload();
 
@@ -129,7 +131,7 @@ void DialogDetachedVideo::OnKeyDown(wxKeyEvent &evt) {
 
 void DialogDetachedVideo::OnVideoOpen() {
 	if (context->project->VideoProvider())
-		SetTitle(wxString::Format(_("Video: %s"), context->project->VideoName().filename().wstring()));
+		SetTitle(fmt_tl("Video: %s", context->project->VideoName().filename()));
 	else {
 		Close();
 		OPT_SET("Video/Detached/Enabled")->SetBool(true);
diff --git a/src/dialog_dummy_video.cpp b/src/dialog_dummy_video.cpp
index 85e5aed89..d46e6f53d 100644
--- a/src/dialog_dummy_video.cpp
+++ b/src/dialog_dummy_video.cpp
@@ -16,6 +16,7 @@
 
 #include "ass_time.h"
 #include "colour_button.h"
+#include "format.h"
 #include "help_button.h"
 #include "libresrc/libresrc.h"
 #include "options.h"
@@ -158,7 +159,7 @@ void DialogDummyVideo::OnResolutionShortcut(wxCommandEvent &e) {
 }
 
 void DialogDummyVideo::UpdateLengthDisplay() {
-	length_display->SetLabel(wxString::Format(_("Resulting duration: %s"), AssTime(length / fps * 1000).GetAssFormated(true)));
+	length_display->SetLabel(fmt_tl("Resulting duration: %s", AssTime(length / fps * 1000).GetAssFormated(true)));
 }
 }
 
diff --git a/src/dialog_export_ebu3264.cpp b/src/dialog_export_ebu3264.cpp
index f2eb54c78..9216416bd 100644
--- a/src/dialog_export_ebu3264.cpp
+++ b/src/dialog_export_ebu3264.cpp
@@ -22,6 +22,7 @@
 #include "dialog_export_ebu3264.h"
 
 #include "compat.h"
+#include "format.h"
 #include "options.h"
 
 #include <libaegisub/charset_conv.h>
@@ -53,7 +54,7 @@ namespace {
 		bool TransferToWindow() override {
 			wxTextCtrl *ctrl = GetCtrl();
 			if (!ctrl) return false;
-			ctrl->SetValue(wxString::Format("%02d:%02d:%02d:%02d", (int)value->h, (int)value->m, (int)value->s, (int)value->f));
+			ctrl->SetValue(fmt_wx("%02d:%02d:%02d:%02d", value->h, value->m, value->s, value->f));
 			return true;
 		}
 
diff --git a/src/dialog_fonts_collector.cpp b/src/dialog_fonts_collector.cpp
index d37d8945a..86938a7ee 100644
--- a/src/dialog_fonts_collector.cpp
+++ b/src/dialog_fonts_collector.cpp
@@ -19,6 +19,7 @@
 
 #include "compat.h"
 #include "dialog_manager.h"
+#include "format.h"
 #include "help_button.h"
 #include "include/aegisub/context.h"
 #include "libresrc/libresrc.h"
@@ -27,6 +28,7 @@
 #include "utils.h"
 
 #include <libaegisub/dispatch.h>
+#include <libaegisub/format_path.h>
 #include <libaegisub/fs.h>
 #include <libaegisub/path.h>
 #include <libaegisub/make_unique.h>
@@ -122,7 +124,7 @@ void FontsCollectorThread(AssFile *subs, agi::fs::path const& destination, FcMod
 				agi::fs::CreateDirectory(destination.parent_path());
 			}
 			catch (agi::fs::FileSystemError const& e) {
-				AppendText(wxString::Format(_("* Failed to create directory '%s': %s.\n"),
+				AppendText(fmt_tl("* Failed to create directory '%s': %s.\n",
 					destination.parent_path().wstring(), to_wx(e.GetMessage())), 2);
 				collector->AddPendingEvent(wxThreadEvent(EVT_COLLECTION_DONE));
 				return;
@@ -133,7 +135,7 @@ void FontsCollectorThread(AssFile *subs, agi::fs::path const& destination, FcMod
 				zip = agi::make_unique<wxZipOutputStream>(*out);
 
 			if (!out->IsOk() || !zip || !zip->IsOk()) {
-				AppendText(wxString::Format(_("* Failed to open %s.\n"), destination.wstring()), 2);
+				AppendText(fmt_tl("* Failed to open %s.\n", destination), 2);
 				collector->AddPendingEvent(wxThreadEvent(EVT_COLLECTION_DONE));
 				return;
 			}
@@ -188,13 +190,13 @@ void FontsCollectorThread(AssFile *subs, agi::fs::path const& destination, FcMod
 			}
 
 			if (ret == 1)
-				AppendText(wxString::Format(_("* Copied %s.\n"), path.wstring()), 1);
+				AppendText(fmt_tl("* Copied %s.\n", path), 1);
 			else if (ret == 2)
-				AppendText(wxString::Format(_("* %s already exists on destination.\n"), path.filename().wstring()), 3);
+				AppendText(fmt_tl("* %s already exists on destination.\n", path.filename()), 3);
 			else if (ret == 3)
-				AppendText(wxString::Format(_("* Symlinked %s.\n"), path.wstring()), 1);
+				AppendText(fmt_tl("* Symlinked %s.\n", path), 1);
 			else {
-				AppendText(wxString::Format(_("* Failed to copy %s.\n"), path.wstring()), 2);
+				AppendText(fmt_tl("* Failed to copy %s.\n", path), 2);
 				allOk = false;
 			}
 		}
diff --git a/src/dialog_jumpto.cpp b/src/dialog_jumpto.cpp
index 1c5fce2b8..ec7919aaf 100644
--- a/src/dialog_jumpto.cpp
+++ b/src/dialog_jumpto.cpp
@@ -29,6 +29,7 @@
 
 #include "ass_time.h"
 #include "async_video_provider.h"
+#include "format.h"
 #include "include/aegisub/context.h"
 #include "libresrc/libresrc.h"
 #include "project.h"
@@ -117,7 +118,7 @@ void DialogJumpTo::OnEditTime (wxCommandEvent &) {
 	long newframe = c->videoController->FrameAtTime(JumpTime->GetTime());
 	if (jumpframe != newframe) {
 		jumpframe = newframe;
-		JumpFrame->ChangeValue(wxString::Format("%li", jumpframe));
+		JumpFrame->ChangeValue(fmt_wx("%d", jumpframe));
 	}
 }
 
diff --git a/src/dialog_log.cpp b/src/dialog_log.cpp
index 89489653d..b7de8892d 100644
--- a/src/dialog_log.cpp
+++ b/src/dialog_log.cpp
@@ -29,6 +29,7 @@
 
 #include "compat.h"
 #include "dialog_manager.h"
+#include "format.h"
 #include "include/aegisub/context.h"
 
 #include <libaegisub/dispatch.h>
@@ -57,26 +58,26 @@ public:
 #ifndef _WIN32
 		tm tmtime;
 		localtime_r(&time, &tmtime);
-		auto log = wxString::Format("%c %02d:%02d:%02d %-6ld <%-25s> [%s:%s:%d]  %s\n",
+		auto log = fmt_wx("%c %02d:%02d:%02d %-6d <%-25s> [%s:%s:%d]  %s\n",
 			agi::log::Severity_ID[sm.severity],
-			(int)tmtime.tm_hour,
-			(int)tmtime.tm_min,
-			(int)tmtime.tm_sec,
-			(long)(sm.time % 1000000000),
+			tmtime.tm_hour,
+			tmtime.tm_min,
+			tmtime.tm_sec,
+			(sm.time % 1000000000),
 			sm.section,
 			sm.file,
 			sm.func,
 			sm.line,
-			to_wx(sm.message));
+			sm.message);
 #else
-		auto log = wxString::Format("%c %-6ld <%-25s> [%s:%s:%d]  %s\n",
+		auto log = fmt_wx("%c %-6ld <%-25s> [%s:%s:%d]  %s\n",
 			agi::log::Severity_ID[sm.severity],
-			(long)(sm.time % 1000000000),
+			(sm.time % 1000000000),
 			sm.section,
 			sm.file,
 			sm.func,
 			sm.line,
-			to_wx(sm.message));
+			sm.message);
 #endif
 
 		if (wxIsMainThread())
diff --git a/src/dialog_selection.cpp b/src/dialog_selection.cpp
index 260ddde84..2adfa764c 100644
--- a/src/dialog_selection.cpp
+++ b/src/dialog_selection.cpp
@@ -18,6 +18,7 @@
 #include "ass_file.h"
 #include "compat.h"
 #include "dialog_manager.h"
+#include "format.h"
 #include "frame_main.h"
 #include "help_button.h"
 #include "include/aegisub/context.h"
@@ -207,14 +208,14 @@ void DialogSelection::Process(wxCommandEvent&) {
 		case Action::SET:
 			new_sel = std::move(matches);
 			message = (count = new_sel.size())
-				? wxString::Format(wxPLURAL("Selection was set to one line", "Selection was set to %u lines", count), (unsigned)count)
+				? fmt_plural(count, "Selection was set to one line", "Selection was set to %u lines", count)
 				: _("Selection was set to no lines");
 			break;
 
 		case Action::ADD:
 			boost::set_union(old_sel, matches, inserter(new_sel, new_sel.begin()));
 			message = (count = new_sel.size() - old_sel.size())
-				? wxString::Format(wxPLURAL("One line was added to selection", "%u lines were added to selection", count), (unsigned)count)
+				? fmt_plural(count, "One line was added to selection", "%u lines were added to selection", count)
 				: _("No lines were added to selection");
 			break;
 
@@ -226,7 +227,7 @@ void DialogSelection::Process(wxCommandEvent&) {
 			boost::set_intersection(old_sel, matches, inserter(new_sel, new_sel.begin()));
 			sub_message:
 			message = (count = old_sel.size() - new_sel.size())
-				? wxString::Format(wxPLURAL("One line was removed from selection", "%u lines were removed from selection", count), (unsigned)count)
+				? fmt_plural(count, "One line was removed from selection", "%u lines were removed from selection", count)
 				: _("No lines were removed from selection");
 			break;
 	}
diff --git a/src/dialog_shift_times.cpp b/src/dialog_shift_times.cpp
index 717428b7e..c6ade8b1f 100644
--- a/src/dialog_shift_times.cpp
+++ b/src/dialog_shift_times.cpp
@@ -19,6 +19,7 @@
 #include "ass_time.h"
 #include "compat.h"
 #include "dialog_manager.h"
+#include "format.h"
 #include "include/aegisub/context.h"
 #include "help_button.h"
 #include "libresrc/libresrc.h"
@@ -92,7 +93,7 @@ static wxString get_history_string(json::Object &obj) {
 
 	wxString shift_amount(to_wx(obj["amount"]));
 	if (!obj["is by time"])
-		shift_amount = wxString::Format(_("%s frames"), shift_amount);
+		shift_amount = fmt_tl("%s frames", shift_amount);
 
 	wxString shift_direction = obj["is backward"] ? _("backward") : _("forward");
 
@@ -109,7 +110,7 @@ static wxString get_history_string(json::Object &obj) {
 	if (sel_mode == 0)
 		lines = _("all");
 	else if (sel_mode == 2)
-		lines = wxString::Format(_("from %d onward"), (int)(int64_t)sel.front()["start"]);
+		lines = fmt_tl("from %d onward", (int64_t)sel.front()["start"]);
 	else {
 		lines += _("sel ");
 		for (auto it = sel.begin(); it != sel.end(); ++it) {
@@ -118,13 +119,13 @@ static wxString get_history_string(json::Object &obj) {
 			if (beg == end)
 				lines += std::to_wstring(beg);
 			else
-				lines += wxString::Format("%d-%d", beg, end);
+				lines += fmt_wx("%d-%d", beg, end);
 			if (it + 1 != sel.end())
 				lines += ";";
 		}
 	}
 
-	return wxString::Format("%s, %s %s, %s, %s", filename, shift_amount, shift_direction, fields, lines);
+	return fmt_wx("%s, %s %s, %s, %s", filename, shift_amount, shift_direction, fields, lines);
 }
 
 DialogShiftTimes::DialogShiftTimes(agi::Context *context)
diff --git a/src/dialog_style_editor.cpp b/src/dialog_style_editor.cpp
index a1b947b11..307565dd4 100644
--- a/src/dialog_style_editor.cpp
+++ b/src/dialog_style_editor.cpp
@@ -149,7 +149,7 @@ DialogStyleEditor::DialogStyleEditor(wxWindow *parent, AssStyle *style, agi::Con
 	};
 
 	auto spin_ctrl = [&](float value, int max_value) {
-		return new wxSpinCtrl(this, -1, wxString::Format("%g", value), wxDefaultPosition, wxSize(60, -1), wxSP_ARROW_KEYS, 0, max_value, value);
+		return new wxSpinCtrl(this, -1, std::to_wstring(value), wxDefaultPosition, wxSize(60, -1), wxSP_ARROW_KEYS, 0, max_value, value);
 	};
 
 	auto num_text_ctrl = [&](double *value, double min, double max, double step) -> wxSpinCtrlDouble * {
diff --git a/src/dialog_style_manager.cpp b/src/dialog_style_manager.cpp
index 07bf4f268..6231b4c4f 100644
--- a/src/dialog_style_manager.cpp
+++ b/src/dialog_style_manager.cpp
@@ -36,8 +36,9 @@
 #include "dialog_manager.h"
 #include "dialog_style_editor.h"
 #include "dialogs.h"
-#include "include/aegisub/context.h"
+#include "format.h"
 #include "help_button.h"
+#include "include/aegisub/context.h"
 #include "libresrc/libresrc.h"
 #include "options.h"
 #include "persist_location.h"
@@ -214,9 +215,9 @@ wxSizer *make_edit_buttons(wxWindow *parent, wxString move_label, wxButton **mov
 template<class Func>
 std::string unique_name(Func name_checker, std::string const& source_name) {
 	if (name_checker(source_name)) {
-		std::string name = from_wx(wxString::Format(_("%s - Copy"), to_wx(source_name)));
+		std::string name = agi::format(_("%s - Copy"), source_name);
 		for (int i = 2; name_checker(name); ++i)
-			name = from_wx(wxString::Format(_("%s - Copy (%d)"), to_wx(source_name), i));
+			name = agi::format(_("%s - Copy (%d)"), source_name, i);
 		return name;
 	}
 	return source_name;
@@ -244,7 +245,7 @@ void add_styles(Func1 name_checker, Func2 style_adder) {
 
 int confirm_delete(int n, wxWindow *parent, wxString const& title) {
 	return wxMessageBox(
-		wxString::Format(wxPLURAL("Are you sure you want to delete this style?", "Are you sure you want to delete these %d styles?", n), n),
+		fmt_plural(n, "Are you sure you want to delete this style?", "Are you sure you want to delete these %d styles?", n),
 		title, wxYES_NO | wxICON_EXCLAMATION, parent);
 }
 
@@ -472,7 +473,7 @@ void DialogStyleManager::OnCatalogNew() {
 	// Warn about bad characters
 	if (badchars_removed) {
 		wxMessageBox(
-			wxString::Format(_("The specified catalog name contains one or more illegal characters. They have been replaced with underscores instead.\nThe catalog has been renamed to \"%s\"."), name),
+			fmt_tl("The specified catalog name contains one or more illegal characters. They have been replaced with underscores instead.\nThe catalog has been renamed to \"%s\".", name),
 			_("Invalid characters"));
 	}
 
@@ -486,7 +487,7 @@ void DialogStyleManager::OnCatalogDelete() {
 	if (CatalogList->GetCount() == 1) return;
 
 	wxString name = CatalogList->GetStringSelection();
-	wxString message = wxString::Format(_("Are you sure you want to delete the storage \"%s\" from the catalog?"), name);
+	wxString message = fmt_tl("Are you sure you want to delete the storage \"%s\" from the catalog?", name);
 	int option = wxMessageBox(message, _("Confirm delete"), wxYES_NO | wxICON_EXCLAMATION , this);
 	if (option == wxYES) {
 		agi::fs::Remove(config::path->Decode("?user/catalog/" + from_wx(name) + ".sty"));
@@ -505,7 +506,7 @@ void DialogStyleManager::OnCopyToStorage() {
 		wxString styleName = CurrentList->GetString(selections[i]);
 
 		if (AssStyle *style = Store.GetStyle(from_wx(styleName))) {
-			if (wxYES == wxMessageBox(wxString::Format(_("There is already a style with the name \"%s\" in the current storage. Overwrite?"),styleName), _("Style name collision"), wxYES_NO)) {
+			if (wxYES == wxMessageBox(fmt_tl("There is already a style with the name \"%s\" in the current storage. Overwrite?", styleName), _("Style name collision"), wxYES_NO)) {
 				*style = *styleMap.at(selections[i]);
 				copied.push_back(styleName);
 			}
@@ -532,7 +533,7 @@ void DialogStyleManager::OnCopyToCurrent() {
 		wxString styleName = StorageList->GetString(selections[i]);
 
 		if (AssStyle *style = c->ass->GetStyle(from_wx(styleName))) {
-			if (wxYES == wxMessageBox(wxString::Format(_("There is already a style with the name \"%s\" in the current script. Overwrite?"), styleName), _("Style name collision"), wxYES_NO)) {
+			if (wxYES == wxMessageBox(fmt_tl("There is already a style with the name \"%s\" in the current script. Overwrite?", styleName), _("Style name collision"), wxYES_NO)) {
 				*style = *Store[selections[i]];
 				copied.push_back(styleName);
 			}
@@ -709,7 +710,7 @@ void DialogStyleManager::OnCurrentImport() {
 		// Check if there is already a style with that name
 		if (AssStyle *existing = c->ass->GetStyle(styles[sel])) {
 			int answer = wxMessageBox(
-				wxString::Format(_("There is already a style with the name \"%s\" in the current script. Overwrite?"), styles[sel]),
+				fmt_tl("There is already a style with the name \"%s\" in the current script. Overwrite?", styles[sel]),
 				_("Style name collision"),
 				wxYES_NO);
 			if (answer == wxYES) {
diff --git a/src/dialog_timing_processor.cpp b/src/dialog_timing_processor.cpp
index 39860d5c0..cce9ab98e 100644
--- a/src/dialog_timing_processor.cpp
+++ b/src/dialog_timing_processor.cpp
@@ -32,6 +32,7 @@
 #include "ass_time.h"
 #include "async_video_provider.h"
 #include "compat.h"
+#include "format.h"
 #include "help_button.h"
 #include "include/aegisub/context.h"
 #include "libresrc/libresrc.h"
@@ -345,7 +346,7 @@ std::vector<AssDialogue*> DialogTimingProcessor::SortDialogues() {
 	for (auto diag : sorted) {
 		if (diag->Start > diag->End) {
 			wxMessageBox(
-				wxString::Format(_("One of the lines in the file (%i) has negative duration. Aborting."), diag->Row),
+				fmt_tl("One of the lines in the file (%i) has negative duration. Aborting.", diag->Row),
 				_("Invalid script"),
 				wxOK | wxICON_ERROR | wxCENTER);
 			sorted.clear();
diff --git a/src/dialog_translation.cpp b/src/dialog_translation.cpp
index a78a6ebc4..e8bdf77cf 100644
--- a/src/dialog_translation.cpp
+++ b/src/dialog_translation.cpp
@@ -28,6 +28,7 @@
 #include "ass_file.h"
 #include "command/command.h"
 #include "compat.h"
+#include "format.h"
 #include "help_button.h"
 #include "libresrc/libresrc.h"
 #include "persist_location.h"
@@ -181,7 +182,7 @@ void DialogTranslation::OnActiveLineChanged(AssDialogue *new_line) {
 void DialogTranslation::OnExternalCommit(int commit_type) {
 	if (commit_type == AssFile::COMMIT_NEW || commit_type & AssFile::COMMIT_DIAG_ADDREM) {
 		line_count = c->ass->Events.size();
-		line_number_display->SetLabel(wxString::Format(_("Current line: %d/%d"), active_line->Row + 1, (int)line_count));
+		line_number_display->SetLabel(fmt_tl("Current line: %d/%d", active_line->Row + 1, line_count));
 	}
 
 	if (commit_type & AssFile::COMMIT_DIAG_TEXT)
@@ -231,7 +232,7 @@ bool DialogTranslation::PrevBlock() {
 }
 
 void DialogTranslation::UpdateDisplay() {
-	line_number_display->SetLabel(wxString::Format(_("Current line: %d/%d"), active_line->Row, (int)line_count));
+	line_number_display->SetLabel(fmt_tl("Current line: %d/%d", active_line->Row, line_count));
 
 	original_text->SetReadOnly(false);
 	original_text->ClearAll();
diff --git a/src/dialog_version_check.cpp b/src/dialog_version_check.cpp
index 865d32b2d..b5d95910e 100644
--- a/src/dialog_version_check.cpp
+++ b/src/dialog_version_check.cpp
@@ -34,13 +34,13 @@
 #endif
 
 #include "compat.h"
+#include "format.h"
 #include "options.h"
 #include "string_codec.h"
 #include "version.h"
 
 #include <libaegisub/dispatch.h>
 #include <libaegisub/exception.h>
-#include <libaegisub/format.h>
 #include <libaegisub/line_iterator.h>
 #include <libaegisub/scoped_ptr.h>
 
@@ -255,7 +255,7 @@ static wxString GetSystemLanguage() {
 	wxString res = GetUILanguage();
 	if (!res)
 		// On an old version of Windows, let's just return the LANGID as a string
-		res = wxString::Format("x-win%04x", GetUserDefaultUILanguage());
+		res = fmt_wx("x-win%04x", GetUserDefaultUILanguage());
 
 	return res;
 }
@@ -287,7 +287,7 @@ void DoCheck(bool interactive) {
 	if (!stream)
 		throw VersionCheckError(from_wx(_("Could not connect to updates server.")));
 
-	stream << agi::format(
+	agi::format(stream,
 		"GET %s?rev=%d&rel=%d&os=%s&lang=%s&aegilang=%s HTTP/1.0\r\n"
 		"User-Agent: Aegisub %s\r\n"
 		"Host: %s\r\n"
@@ -309,7 +309,7 @@ void DoCheck(bool interactive) {
 	if (!stream || http_version.substr(0, 5) != "HTTP/")
 		throw VersionCheckError(from_wx(_("Could not download from updates server.")));
 	if (status_code != 200)
-		throw VersionCheckError(from_wx(wxString::Format(_("HTTP request failed, got HTTP response %d."), status_code)));
+		throw VersionCheckError(agi::format(_("HTTP request failed, got HTTP response %d."), status_code));
 
 	stream.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
 
@@ -371,8 +371,8 @@ void PerformVersionCheck(bool interactive) {
 			DoCheck(interactive);
 		}
 		catch (const agi::Exception &e) {
-			PostErrorEvent(interactive, wxString::Format(
-				_("There was an error checking for updates to Aegisub:\n%s\n\nIf other applications can access the Internet fine, this is probably a temporary server problem on our end."),
+			PostErrorEvent(interactive, fmt_tl(
+				"There was an error checking for updates to Aegisub:\n%s\n\nIf other applications can access the Internet fine, this is probably a temporary server problem on our end.",
 				e.GetMessage()));
 		}
 		catch (...) {
diff --git a/src/dialog_video_details.cpp b/src/dialog_video_details.cpp
index 436ad2d56..7ed9c5141 100644
--- a/src/dialog_video_details.cpp
+++ b/src/dialog_video_details.cpp
@@ -30,6 +30,7 @@
 #include "ass_time.h"
 #include "async_video_provider.h"
 #include "compat.h"
+#include "format.h"
 #include "include/aegisub/context.h"
 #include "project.h"
 
@@ -62,10 +63,10 @@ DialogVideoDetails::DialogVideoDetails(agi::Context *c)
 		fg->Add(new wxTextCtrl(this, -1, value, wxDefaultPosition, wxSize(300,-1), wxTE_READONLY), 0, wxALIGN_CENTRE_VERTICAL | wxEXPAND);
 	};
 	make_field(_("File name:"), c->project->VideoName().wstring());
-	make_field(_("FPS:"), wxString::Format("%.3f", fps.FPS()));
-	make_field(_("Resolution:"), wxString::Format("%dx%d (%d:%d)", width, height, ar.numerator(), ar.denominator()));
-	make_field(_("Length:"), wxString::Format(wxPLURAL("1 frame", "%d frames (%s)", framecount),
-		framecount, to_wx(AssTime(fps.TimeAtFrame(framecount - 1)).GetAssFormated(true))));
+	make_field(_("FPS:"), fmt_wx("%.3f", fps.FPS()));
+	make_field(_("Resolution:"), fmt_wx("%dx%d (%d:%d)", width, height, ar.numerator(), ar.denominator()));
+	make_field(_("Length:"), fmt_plural(framecount, "1 frame", "%d frames (%s)",
+		framecount, AssTime(fps.TimeAtFrame(framecount - 1)).GetAssFormated(true)));
 	make_field(_("Decoder:"), to_wx(provider->GetDecoderName()));
 
 	wxStaticBoxSizer *video_sizer = new wxStaticBoxSizer(wxVERTICAL, this, _("Video"));
diff --git a/src/dialog_video_properties.cpp b/src/dialog_video_properties.cpp
index 00ece3407..3d2dad45b 100644
--- a/src/dialog_video_properties.cpp
+++ b/src/dialog_video_properties.cpp
@@ -16,6 +16,7 @@
 
 #include "ass_file.h"
 #include "async_video_provider.h"
+#include "format.h"
 #include "options.h"
 #include "resolution_resampler.h"
 
@@ -43,7 +44,7 @@ public:
 	Prompt(wxWindow *parent, bool ar_changed, int sx, int sy, int vx, int vy)
 	: wxDialog(parent, -1, _("Resolution mismatch"))
 	{
-		auto label_text = wxString::Format(_("The resolution of the loaded video and the resolution specified for the subtitles don't match.\n\nVideo resolution:\t%d x %d\nScript resolution:\t%d x %d\n\nChange subtitles resolution to match video?"), vx, vy, sx, sy);
+		auto label_text = fmt_tl("The resolution of the loaded video and the resolution specified for the subtitles don't match.\n\nVideo resolution:\t%d x %d\nScript resolution:\t%d x %d\n\nChange subtitles resolution to match video?", vx, vy, sx, sy);
 
 		auto sizer = new wxBoxSizer(wxVERTICAL);
 		sizer->Add(new wxStaticText(this, -1, label_text), wxSizerFlags().Border());
diff --git a/src/export_framerate.cpp b/src/export_framerate.cpp
index d27b9e4e7..024489f64 100644
--- a/src/export_framerate.cpp
+++ b/src/export_framerate.cpp
@@ -33,6 +33,7 @@
 #include "ass_file.h"
 #include "async_video_provider.h"
 #include "compat.h"
+#include "format.h"
 #include "include/aegisub/context.h"
 #include "project.h"
 
@@ -68,9 +69,9 @@ wxWindow *AssTransformFramerateFilter::GetConfigDialogWindow(wxWindow *parent, a
 	wxString initialInput;
 	auto FromVideo = new wxButton(base,-1,_("From &video"));
 	if (Input.IsLoaded()) {
-		initialInput = wxString::Format("%2.3f", Input.FPS());
+		initialInput = fmt_wx("%2.3f", Input.FPS());
 		FromVideo->Bind(wxEVT_BUTTON, [=](wxCommandEvent&) {
-			InputFramerate->SetValue(wxString::Format("%g", c->project->Timecodes().FPS()));
+			InputFramerate->SetValue(fmt_wx("%g", c->project->Timecodes().FPS()));
 		});
 	}
 	else {
diff --git a/src/ffmpegsource_common.cpp b/src/ffmpegsource_common.cpp
index 9c806dd94..1ff0776e9 100644
--- a/src/ffmpegsource_common.cpp
+++ b/src/ffmpegsource_common.cpp
@@ -36,6 +36,7 @@
 #include "ffmpegsource_common.h"
 
 #include "compat.h"
+#include "format.h"
 #include "options.h"
 #include "utils.h"
 
@@ -141,7 +142,7 @@ int FFmpegSourceProvider::AskForTrackSelection(const std::map<int, std::string>
 	wxArrayString Choices;
 
 	for (auto const& track : TrackList) {
-		Choices.Add(wxString::Format(_("Track %02d: %s"), track.first, to_wx(track.second)));
+		Choices.Add(agi::format(_("Track %02d: %s"), track.first, to_wx(track.second)));
 		TrackNumbers.push_back(track.first);
 	}
 
diff --git a/src/font_file_lister.cpp b/src/font_file_lister.cpp
index 0a40a68d0..8c0b6becb 100644
--- a/src/font_file_lister.cpp
+++ b/src/font_file_lister.cpp
@@ -25,6 +25,10 @@
 #include "ass_file.h"
 #include "ass_style.h"
 #include "compat.h"
+#include "format.h"
+
+#include <libaegisub/format_flyweight.h>
+#include <libaegisub/format_path.h>
 
 #include <algorithm>
 #include <tuple>
@@ -39,7 +43,7 @@ namespace {
 			if (!u_isUWhiteSpace(c.GetValue()))
 				printable += c;
 			else {
-				unprintable += wxString::Format("\n - U+%04X ", c.GetValue());
+				unprintable += fmt_wx("\n - U+%04X ", c.GetValue());
 				UErrorCode ec;
 				char buf[1024];
 				auto len = u_charName(c.GetValue(), U_EXTENDED_CHAR_NAME, buf, sizeof buf, &ec);
@@ -65,7 +69,7 @@ void FontCollector::ProcessDialogueLine(const AssDialogue *line, int index) {
 
 	auto style_it = styles.find(line->Style);
 	if (style_it == end(styles)) {
-		status_callback(wxString::Format(_("Style '%s' does not exist\n"), to_wx(line->Style)), 2);
+		status_callback(fmt_tl("Style '%s' does not exist\n", line->Style), 2);
 		++missing;
 		return;
 	}
@@ -131,26 +135,26 @@ void FontCollector::ProcessChunk(std::pair<StyleInfo, UsageData> const& style) {
 	FontFileLister::CollectionResult res = lister.GetFontPaths(style.first.facename, style.first.bold, style.first.italic, style.second.chars);
 
 	if (res.paths.empty()) {
-		status_callback(wxString::Format(_("Could not find font '%s'\n"), to_wx(style.first.facename)), 2);
+		status_callback(fmt_tl("Could not find font '%s'\n", style.first.facename), 2);
 		PrintUsage(style.second);
 		++missing;
 	}
 	else {
 		for (auto& elem : res.paths) {
 			if (results.insert(elem).second)
-				status_callback(wxString::Format(_("Found '%s' at '%s'\n"), to_wx(style.first.facename), elem.make_preferred().wstring()), 0);
+				status_callback(fmt_tl("Found '%s' at '%s'\n", style.first.facename, elem.make_preferred()), 0);
 		}
 
 		if (res.fake_bold)
-			status_callback(wxString::Format(_("'%s' does not have a bold variant.\n"), to_wx(style.first.facename)), 3);
+			status_callback(fmt_tl("'%s' does not have a bold variant.\n", style.first.facename), 3);
 		if (res.fake_italic)
-			status_callback(wxString::Format(_("'%s' does not have an italic variant.\n"), to_wx(style.first.facename)), 3);
+			status_callback(fmt_tl("'%s' does not have an italic variant.\n", style.first.facename), 3);
 
 		if (res.missing.size()) {
 			if (res.missing.size() > 50)
-				status_callback(wxString::Format(_("'%s' is missing %d glyphs used.\n"), to_wx(style.first.facename), (int)res.missing.size()), 2);
+				status_callback(fmt_tl("'%s' is missing %d glyphs used.\n", style.first.facename, res.missing.size()), 2);
 			else if (res.missing.size() > 0)
-				status_callback(wxString::Format(_("'%s' is missing the following glyphs used: %s\n"), to_wx(style.first.facename), format_missing(res.missing)), 2);
+				status_callback(fmt_tl("'%s' is missing the following glyphs used: %s\n", style.first.facename, format_missing(res.missing)), 2);
 			PrintUsage(style.second);
 			++missing_glyphs;
 		}
@@ -161,15 +165,15 @@ void FontCollector::ProcessChunk(std::pair<StyleInfo, UsageData> const& style) {
 
 void FontCollector::PrintUsage(UsageData const& data) {
 	if (data.styles.size()) {
-		status_callback(wxString::Format(_("Used in styles:\n")), 2);
+		status_callback(_("Used in styles:\n"), 2);
 		for (auto const& style : data.styles)
-			status_callback(wxString::Format("  - %s\n", style), 2);
+			status_callback(fmt_wx("  - %s\n", style), 2);
 	}
 
 	if (data.lines.size()) {
-		status_callback(wxString::Format(_("Used on lines:")), 2);
+		status_callback(_("Used on lines:"), 2);
 		for (int line : data.lines)
-			status_callback(wxString::Format(" %d", line), 2);
+			status_callback(fmt_wx(" %d", line), 2);
 		status_callback("\n", 2);
 	}
 	status_callback("\n", 2);
@@ -204,12 +208,11 @@ std::vector<agi::fs::path> FontCollector::GetFontPaths(const AssFile *file) {
 	if (missing == 0)
 		status_callback(_("All fonts found.\n"), 1);
 	else
-		status_callback(wxString::Format(wxPLURAL("One font could not be found\n", "%d fonts could not be found.\n", missing), missing), 2);
+		status_callback(fmt_plural(missing, "One font could not be found\n", "%d fonts could not be found.\n", missing), 2);
 	if (missing_glyphs != 0)
-		status_callback(wxString::Format(wxPLURAL(
-				"One font was found, but was missing glyphs used in the script.\n",
-				"%d fonts were found, but were missing glyphs used in the script.\n",
-				missing_glyphs),
+		status_callback(fmt_plural(missing_glyphs,
+			"One font was found, but was missing glyphs used in the script.\n",
+			"%d fonts were found, but were missing glyphs used in the script.\n",
 			missing_glyphs), 2);
 
 	return paths;
diff --git a/src/format.h b/src/format.h
new file mode 100644
index 000000000..381fb900c
--- /dev/null
+++ b/src/format.h
@@ -0,0 +1,64 @@
+// Copyright (c) 2014, Thomas Goyne <plorkyeran@aegisub.org>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+// Aegisub Project http://www.aegisub.org/
+
+#include <libaegisub/format.h>
+
+#include <wx/string.h>
+#include <wx/translation.h>
+
+namespace agi {
+template<>
+struct writer<char, wxString> {
+	static void write(std::basic_ostream<char>& out, int max_len, wxString const& value) {
+		format_detail::do_write_str(out, value.wx_str(),
+			format_detail::actual_len(max_len, value.wx_str()));
+	}
+};
+
+template<>
+struct writer<wchar_t, wxString> {
+	static void write(std::basic_ostream<wchar_t>& out, int max_len, wxString const& value) {
+		format_detail::do_write_str(out, value.wx_str(),
+			format_detail::actual_len(max_len, value.wx_str()));
+	}
+};
+
+template<typename... Args>
+std::string format(wxString const& fmt, Args&&... args) {
+	boost::interprocess::basic_vectorstream<std::basic_string<char>> out;
+	format(out, (const char *)fmt.utf8_str(), std::forward<Args>(args)...);
+	return out.vector();
+}
+
+template<typename... Args>
+wxString wxformat(wxString const& fmt, Args&&... args) {
+	boost::interprocess::basic_vectorstream<std::basic_string<wxChar>> out;
+	format(out, fmt.wx_str(), std::forward<Args>(args)...);
+	return out.vector();
+}
+
+template<typename... Args>
+wxString wxformat(const wxChar *fmt, Args&&... args) {
+	boost::interprocess::basic_vectorstream<std::basic_string<wxChar>> out;
+	format(out, fmt, std::forward<Args>(args)...);
+	return out.vector();
+}
+}
+
+#define fmt_wx(str, ...) agi::wxformat(wxS(str), __VA_ARGS__)
+#define fmt_tl(str, ...) agi::wxformat(wxGetTranslation(wxS(str)), __VA_ARGS__)
+#define fmt_plural(n, sing, plural, ...) \
+	agi::wxformat(wxGetTranslation(wxS(sing), wxS(plural), (n)), __VA_ARGS__)
diff --git a/src/help_button.cpp b/src/help_button.cpp
index 674b4215e..23db3d3b6 100644
--- a/src/help_button.cpp
+++ b/src/help_button.cpp
@@ -29,6 +29,8 @@
 
 #include "help_button.h"
 
+#include "format.h"
+
 #include <libaegisub/exception.h>
 
 #include <boost/container/flat_map.hpp>
@@ -79,5 +81,5 @@ void HelpButton::OpenPage(wxString const& pageID) {
 	wxString section;
 	page = page.BeforeFirst('#', &section);
 
-	wxLaunchDefaultBrowser(wxString::Format("http://docs.aegisub.org/3.1/%s/#%s", page, section));
+	wxLaunchDefaultBrowser(fmt_wx("http://docs.aegisub.org/3.1/%s/#%s", page, section));
 }
diff --git a/src/main.cpp b/src/main.cpp
index 5714f9f40..de7112113 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -44,6 +44,7 @@
 #include "dialogs.h"
 #include "export_fixstyle.h"
 #include "export_framerate.h"
+#include "format.h"
 #include "frame_main.h"
 #include "include/aegisub/context.h"
 #include "libresrc/libresrc.h"
@@ -55,7 +56,7 @@
 #include "version.h"
 
 #include <libaegisub/dispatch.h>
-#include <libaegisub/format.h>
+#include <libaegisub/format_path.h>
 #include <libaegisub/fs.h>
 #include <libaegisub/io.h>
 #include <libaegisub/log.h>
@@ -386,12 +387,12 @@ static void UnhandledExeception(bool stackWalk, agi::Context *c) {
 			crash_writer::Write();
 
 		// Inform user of crash.
-		wxMessageBox(wxString::Format(exception_message, path.wstring()), _("Program error"), wxOK | wxICON_ERROR | wxCENTER, nullptr);
+		wxMessageBox(agi::wxformat(exception_message, path), _("Program error"), wxOK | wxICON_ERROR | wxCENTER, nullptr);
 	}
 	else if (LastStartupState) {
 		if (stackWalk)
 			crash_writer::Write();
-		wxMessageBox(wxString::Format("Aegisub has crashed while starting up!\n\nThe last startup step attempted was: %s.", LastStartupState), _("Program error"), wxOK | wxICON_ERROR | wxCENTER);
+		wxMessageBox(fmt_wx("Aegisub has crashed while starting up!\n\nThe last startup step attempted was: %s.", LastStartupState), _("Program error"), wxOK | wxICON_ERROR | wxCENTER);
 	}
 #endif
 }
@@ -405,7 +406,7 @@ void AegisubApp::OnFatalException() {
 }
 
 #define SHOW_EXCEPTION(str) \
-	wxMessageBox(wxString::Format(_("An unexpected error has occurred. Please save your work and restart Aegisub.\n\nError Message: %s"), str), \
+	wxMessageBox(fmt_tl("An unexpected error has occurred. Please save your work and restart Aegisub.\n\nError Message: %s", str), \
 				"Exception in event handler", wxOK | wxICON_ERROR | wxCENTER | wxSTAY_ON_TOP)
 void AegisubApp::HandleEvent(wxEvtHandler *handler, wxEventFunction func, wxEvent& event) const {
 	try {
diff --git a/src/menu.cpp b/src/menu.cpp
index 8a51c4d7b..4a34312da 100644
--- a/src/menu.cpp
+++ b/src/menu.cpp
@@ -24,6 +24,7 @@
 #include "auto4_base.h"
 #include "command/command.h"
 #include "compat.h"
+#include "format.h"
 #include "libresrc/libresrc.h"
 #include "main.h"
 #include "options.h"
@@ -37,6 +38,7 @@
 #include <libaegisub/split.h>
 
 #include <algorithm>
+#include <boost/algorithm/string/case_conv.hpp>
 #include <boost/range/algorithm_ext/push_back.hpp>
 #include <vector>
 #include <wx/app.h>
@@ -61,7 +63,7 @@ class MruMenu final : public wxMenu {
 		for (size_t i = GetMenuItemCount(); i < new_size; ++i) {
 			if (i >= items.size()) {
 				items.push_back(new wxMenuItem(this, MENU_ID_BASE + cmds->size(), "_"));
-				cmds->push_back(from_wx(wxString::Format("recent/%s/%d", to_wx(type).Lower(), (int)i)));
+				cmds->push_back(agi::format("recent/%s/%d", boost::to_lower_copy(type), i));
 			}
 			Append(items[i]);
 		}
@@ -96,7 +98,7 @@ public:
 			wxString name = it->wstring();
 			if (!name.StartsWith("?"))
 				name = it->filename().wstring();
-			items[i]->SetItemLabel(wxString::Format("%s%d %s",
+			items[i]->SetItemLabel(fmt_wx("%s%d %s",
 				i <= 9 ? "&" : "", i + 1,
 				name));
 			items[i]->Enable(true);
diff --git a/src/preferences_base.cpp b/src/preferences_base.cpp
index 25e66fab4..7a664f0fe 100644
--- a/src/preferences_base.cpp
+++ b/src/preferences_base.cpp
@@ -130,7 +130,7 @@ wxControl *OptionPage::OptionAdd(wxFlexGridSizer *flex, const wxString &name, co
 		}
 
 		case agi::OptionType::Double: {
-			wxSpinCtrlDouble *scd = new wxSpinCtrlDouble(this, -1, wxString::Format("%g", opt->GetDouble()), wxDefaultPosition, wxDefaultSize, wxSP_ARROW_KEYS, min, max, opt->GetDouble(), inc);
+			wxSpinCtrlDouble *scd = new wxSpinCtrlDouble(this, -1, std::to_wstring(opt->GetDouble()), wxDefaultPosition, wxDefaultSize, wxSP_ARROW_KEYS, min, max, opt->GetDouble(), inc);
 			scd->Bind(wxEVT_SPINCTRL, DoubleUpdater(opt_name, parent));
 			Add(flex, name, scd);
 			return scd;
diff --git a/src/project.cpp b/src/project.cpp
index 395fd52f7..1471d436d 100644
--- a/src/project.cpp
+++ b/src/project.cpp
@@ -23,6 +23,7 @@
 #include "compat.h"
 #include "dialog_progress.h"
 #include "dialogs.h"
+#include "format.h"
 #include "include/aegisub/audio_provider.h"
 #include "include/aegisub/context.h"
 #include "include/aegisub/video_provider.h"
@@ -32,6 +33,7 @@
 #include "video_controller.h"
 #include "video_display.h"
 
+#include <libaegisub/format_path.h>
 #include <libaegisub/fs.h>
 #include <libaegisub/keyframe.h>
 #include <libaegisub/log.h>
@@ -165,7 +167,7 @@ void Project::LoadUnloadFiles() {
 			if (p.empty())
 				str += "\n" + unload;
 			else
-				str += "\n" + wxString::Format(load, p.wstring());
+				str += "\n" + agi::wxformat(load, p);
 		};
 
 		if (audio != audio_file)
diff --git a/src/search_replace_engine.cpp b/src/search_replace_engine.cpp
index 9faf90db9..e0e2066b4 100644
--- a/src/search_replace_engine.cpp
+++ b/src/search_replace_engine.cpp
@@ -18,6 +18,7 @@
 
 #include "ass_dialogue.h"
 #include "ass_file.h"
+#include "format.h"
 #include "include/aegisub/context.h"
 #include "selection_controller.h"
 #include "text_selection_controller.h"
@@ -328,7 +329,7 @@ bool SearchReplaceEngine::ReplaceAll() {
 
 	if (count > 0) {
 		context->ass->Commit(_("replace"), AssFile::COMMIT_DIAG_TEXT);
-		wxMessageBox(wxString::Format(wxPLURAL("One match was replaced.", "%d matches were replaced.", count), (int)count));
+		wxMessageBox(fmt_plural(count, "One match was replaced.", "%d matches were replaced.", (int)count));
 	}
 	else {
 		wxMessageBox(_("No matches found."));
diff --git a/src/subs_controller.cpp b/src/subs_controller.cpp
index 358811ba2..a2d9f8b1b 100644
--- a/src/subs_controller.cpp
+++ b/src/subs_controller.cpp
@@ -23,6 +23,7 @@
 #include "ass_style.h"
 #include "compat.h"
 #include "command/command.h"
+#include "format.h"
 #include "frame_main.h"
 #include "include/aegisub/context.h"
 #include "options.h"
@@ -31,7 +32,7 @@
 #include "subtitle_format.h"
 #include "text_selection_controller.h"
 
-#include <libaegisub/format.h>
+#include <libaegisub/format_path.h>
 #include <libaegisub/fs.h>
 #include <libaegisub/path.h>
 #include <libaegisub/util.h>
@@ -154,7 +155,7 @@ SubsController::SubsController(agi::Context *context)
 		try {
 			auto fn = AutoSave();
 			if (!fn.empty())
-				context->frame->StatusTimeout(wxString::Format(_("File backup saved as \"%s\"."), fn.wstring()));
+				context->frame->StatusTimeout(fmt_tl("File backup saved as \"%s\".", fn));
 		}
 		catch (const agi::Exception& err) {
 			context->frame->StatusTimeout(to_wx("Exception when attempting to autosave file: " + err.GetMessage()));
@@ -254,7 +255,7 @@ int SubsController::TryToClose(bool allow_cancel) const {
 	int flags = wxYES_NO;
 	if (allow_cancel)
 		flags |= wxCANCEL;
-	int result = wxMessageBox(wxString::Format(_("Do you want to save changes to %s?"), Filename().wstring()), _("Unsaved changes"), flags, context->parent);
+	int result = wxMessageBox(fmt_tl("Do you want to save changes to %s?", Filename()), _("Unsaved changes"), flags, context->parent);
 	if (result == wxYES) {
 		cmd::call("subtitle/save", context);
 		// If it fails saving, return cancel anyway
diff --git a/src/subs_edit_box.cpp b/src/subs_edit_box.cpp
index 8c4f78680..2680d9fba 100644
--- a/src/subs_edit_box.cpp
+++ b/src/subs_edit_box.cpp
@@ -613,7 +613,7 @@ void SubsEditBox::UpdateCharacterCount(std::string const& text) {
 	if (OPT_GET("Subtitle/Character Counter/Ignore Punctuation")->GetBool())
 		ignore |= agi::IGNORE_PUNCTUATION;
 	size_t length = agi::MaxLineLength(text, ignore);
-	char_count->SetValue(wxString::Format("%lu", (unsigned long)length));
+	char_count->SetValue(std::to_wstring(length));
 	size_t limit = (size_t)OPT_GET("Subtitle/Character Limit")->GetInt();
 	if (limit && length > limit)
 		char_count->SetBackgroundColour(to_wx(OPT_GET("Colour/Subtitle/Syntax/Background/Error")->GetColor()));
diff --git a/src/subs_edit_ctrl.cpp b/src/subs_edit_ctrl.cpp
index 59dc2de1d..9177659dc 100644
--- a/src/subs_edit_ctrl.cpp
+++ b/src/subs_edit_ctrl.cpp
@@ -37,6 +37,7 @@
 #include "ass_dialogue.h"
 #include "command/command.h"
 #include "compat.h"
+#include "format.h"
 #include "options.h"
 #include "include/aegisub/context.h"
 #include "include/aegisub/spellchecker.h"
@@ -380,7 +381,7 @@ void SubsTextEditCtrl::AddSpellCheckerEntries(wxMenu &menu) {
 	if (currentWord.empty()) return;
 
 	if (spellchecker->CanRemoveWord(currentWord))
-		menu.Append(EDIT_MENU_REMOVE_FROM_DICT, wxString::Format(_("Remove \"%s\" from dictionary"), to_wx(currentWord)));
+		menu.Append(EDIT_MENU_REMOVE_FROM_DICT, fmt_tl("Remove \"%s\" from dictionary", currentWord));
 
 	sugs = spellchecker->GetSuggestions(currentWord);
 	if (spellchecker->CheckWord(currentWord)) {
@@ -391,7 +392,7 @@ void SubsTextEditCtrl::AddSpellCheckerEntries(wxMenu &menu) {
 			for (size_t i = 0; i < sugs.size(); ++i)
 				subMenu->Append(EDIT_MENU_SUGGESTIONS+i, to_wx(sugs[i]));
 
-			menu.Append(-1, wxString::Format(_("Spell checker suggestions for \"%s\""), to_wx(currentWord)), subMenu);
+			menu.Append(-1, fmt_tl("Spell checker suggestions for \"%s\"", currentWord), subMenu);
 		}
 	}
 	else {
@@ -402,7 +403,7 @@ void SubsTextEditCtrl::AddSpellCheckerEntries(wxMenu &menu) {
 			menu.Append(EDIT_MENU_SUGGESTIONS+i, to_wx(sugs[i]));
 
 		// Append "add word"
-		menu.Append(EDIT_MENU_ADD_TO_DICT, wxString::Format(_("Add \"%s\" to dictionary"), to_wx(currentWord)))->Enable(spellchecker->CanAddWord(currentWord));
+		menu.Append(EDIT_MENU_ADD_TO_DICT, fmt_tl("Add \"%s\" to dictionary", currentWord))->Enable(spellchecker->CanAddWord(currentWord));
 	}
 }
 
@@ -437,7 +438,7 @@ void SubsTextEditCtrl::AddThesaurusEntries(wxMenu &menu) {
 			}
 		}
 
-		menu.Append(-1, wxString::Format(_("Thesaurus suggestions for \"%s\""), to_wx(currentWord)), thesMenu);
+		menu.Append(-1, fmt_tl("Thesaurus suggestions for \"%s\"", currentWord), thesMenu);
 	}
 	else
 		menu.Append(EDIT_MENU_THESAURUS,_("No thesaurus suggestions"))->Enable(false);
diff --git a/src/subtitle_format.cpp b/src/subtitle_format.cpp
index f8531c93f..11fe3b19a 100644
--- a/src/subtitle_format.cpp
+++ b/src/subtitle_format.cpp
@@ -34,12 +34,10 @@
 
 #include "subtitle_format.h"
 
-#include <wx/intl.h>
-#include <wx/choicdlg.h> // Keep this last so wxUSE_CHOICEDLG is set.
-
 #include "ass_dialogue.h"
 #include "ass_file.h"
 #include "compat.h"
+#include "format.h"
 #include "subtitle_format_ass.h"
 #include "subtitle_format_ebu3264.h"
 #include "subtitle_format_encore.h"
@@ -56,6 +54,7 @@
 #include <algorithm>
 #include <boost/algorithm/string/join.hpp>
 #include <boost/algorithm/string/replace.hpp>
+#include <wx/choicdlg.h>
 
 namespace {
 	std::vector<std::unique_ptr<SubtitleFormat>> formats;
@@ -98,7 +97,7 @@ agi::vfr::Framerate SubtitleFormat::AskForFPS(bool allow_vfr, bool show_smpte, a
 	if (fps.IsLoaded()) {
 		vidLoaded = true;
 		if (!fps.IsVFR())
-			choices.Add(wxString::Format(_("From video (%g)"), fps.FPS()));
+			choices.Add(fmt_tl("From video (%g)", fps.FPS()));
 		else if (allow_vfr)
 			choices.Add(_("From video (VFR)"));
 		else
diff --git a/src/subtitle_format_ebu3264.cpp b/src/subtitle_format_ebu3264.cpp
index 9b97e9bbd..2e3d98172 100644
--- a/src/subtitle_format_ebu3264.cpp
+++ b/src/subtitle_format_ebu3264.cpp
@@ -28,6 +28,7 @@
 #include "ass_style.h"
 #include "compat.h"
 #include "dialog_export_ebu3264.h"
+#include "format.h"
 #include "options.h"
 #include "text_file_writer.h"
 
@@ -404,7 +405,7 @@ namespace
 			else if (!imline.CheckLineLengths(export_settings.max_line_length))
 			{
 				if (export_settings.line_wrapping_mode == EbuExportSettings::AbortOverLength)
-					throw Ebu3264SubtitleFormat::ConversionFailed(from_wx(wxString::Format(_("Line over maximum length: %s"), line.Text.get())));
+					throw Ebu3264SubtitleFormat::ConversionFailed(agi::format(_("Line over maximum length: %s"), line.Text));
 				else // skip over-long lines
 					subs_list.pop_back();
 			}
diff --git a/src/utils.cpp b/src/utils.cpp
index 6eb8afc3f..1eefa80da 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -30,11 +30,11 @@
 #include "utils.h"
 
 #include "compat.h"
+#include "format.h"
 #include "options.h"
 #include "retina_helper.h"
 
 #include <libaegisub/dispatch.h>
-#include <libaegisub/format.h>
 #include <libaegisub/fs.h>
 #include <libaegisub/log.h>
 
@@ -72,7 +72,7 @@ wxString PrettySize(int bytes) {
 		fmt = "%.2f";
 	else if (size < 100)
 		fmt = "%1.f";
-	return wxString::Format(fmt, size) + " " + suffix[i];
+	return agi::wxformat(fmt, size) + " " + suffix[i];
 }
 
 std::string float_to_string(double val) {
@@ -104,7 +104,7 @@ void RestartAegisub() {
 	std::string helper_path = agi::util::GetBundleAuxillaryExecutablePath("restart-helper");
 	if (bundle_path.empty() || helper_path.empty()) return;
 
-	wxString exec = wxString::Format("\"%s\" /usr/bin/open -n \"%s\"'", to_wx(helper_path), to_wx(bundle_path));
+	wxString exec = fmt_wx("\"%s\" /usr/bin/open -n \"%s\"'", helper_path, bundle_path);
 	LOG_I("util/restart/exec") << exec;
 	wxExecute(exec);
 #else
diff --git a/src/validators.cpp b/src/validators.cpp
index f839722be..2ec12cd65 100644
--- a/src/validators.cpp
+++ b/src/validators.cpp
@@ -132,12 +132,12 @@ void DoubleValidator::OnChar(wxKeyEvent& event) {
 }
 
 bool DoubleValidator::TransferToWindow() {
-	auto str = wxString::Format("%g", *value);
+	auto str = std::to_wstring(*value);
 	if (decimal_sep != '.')
-		std::replace(str.begin(), str.end(), (wxChar)'.', decimal_sep);
+		std::replace(str.begin(), str.end(), L'.', decimal_sep);
 	if (str.find(decimal_sep) != str.npos) {
-		while (str.Last() == '0')
-			str.RemoveLast();
+		while (str.back() == '0')
+			str.pop_back();
 	}
 	static_cast<wxTextCtrl *>(GetWindow())->SetValue(str);
 	return true;
diff --git a/src/video_box.cpp b/src/video_box.cpp
index b8a120e55..96a1d5948 100644
--- a/src/video_box.cpp
+++ b/src/video_box.cpp
@@ -32,6 +32,7 @@
 #include "ass_dialogue.h"
 #include "ass_file.h"
 #include "compat.h"
+#include "format.h"
 #include "include/aegisub/context.h"
 #include "include/aegisub/toolbar.h"
 #include "options.h"
@@ -65,7 +66,7 @@ VideoBox::VideoBox(wxWindow *parent, bool isDetached, agi::Context *context)
 
 	wxArrayString choices;
 	for (int i = 1; i <= 24; ++i)
-		choices.Add(wxString::Format("%g%%", i * 12.5));
+		choices.Add(fmt_wx("%g%%", i * 12.5));
 	auto zoomBox = new wxComboBox(this, -1, "75%", wxDefaultPosition, wxDefaultSize, choices, wxCB_DROPDOWN | wxTE_PROCESS_ENTER);
 
 	auto visualToolBar = toolbar::GetToolbar(this, "visual_tools", context, "Video", true);
@@ -114,7 +115,7 @@ void VideoBox::UpdateTimeBoxes() {
 	int time = context->videoController->TimeAtFrame(frame, agi::vfr::EXACT);
 
 	// Set the text box for frame number and time
-	VideoPosition->SetValue(wxString::Format("%s - %d", AssTime(time).GetAssFormated(true), frame));
+	VideoPosition->SetValue(fmt_wx("%s - %d", AssTime(time).GetAssFormated(true), frame));
 	if (boost::binary_search(context->project->Keyframes(), frame)) {
 		// Set the background color to indicate this is a keyframe
 		VideoPosition->SetBackgroundColour(to_wx(OPT_GET("Colour/Subtitle Grid/Background/Selection")->GetColor()));
@@ -129,7 +130,7 @@ void VideoBox::UpdateTimeBoxes() {
 	if (!active_line)
 		VideoSubsPos->SetValue("");
 	else {
-		VideoSubsPos->SetValue(wxString::Format(
+		VideoSubsPos->SetValue(fmt_wx(
 			"%+dms; %+dms",
 			time - active_line->Start,
 			time - active_line->End));
diff --git a/src/video_display.cpp b/src/video_display.cpp
index 83268e3dc..620869b50 100644
--- a/src/video_display.cpp
+++ b/src/video_display.cpp
@@ -38,6 +38,7 @@
 #include "async_video_provider.h"
 #include "command/command.h"
 #include "compat.h"
+#include "format.h"
 #include "include/aegisub/context.h"
 #include "include/aegisub/hotkey.h"
 #include "include/aegisub/menu.h"
@@ -71,7 +72,7 @@ int attribList[] = { WX_GL_RGBA , WX_GL_DOUBLEBUFFER, WX_GL_STENCIL_SIZE, 8, 0 }
 class OpenGlException final : public agi::Exception {
 public:
 	OpenGlException(const char *func, int err)
-	: agi::Exception(from_wx(wxString::Format("%s failed with error code %d", func, err)))
+	: agi::Exception(agi::format("%s failed with error code %d", func, err))
 	{ }
 };
 
@@ -93,7 +94,7 @@ VideoDisplay::VideoDisplay(wxToolBar *toolbar, bool freeSize, wxComboBox *zoomBo
 	SetZoom(new_zoom);
 }))
 {
-	zoomBox->SetValue(wxString::Format("%g%%", zoomValue * 100.));
+	zoomBox->SetValue(fmt_wx("%g%%", zoomValue * 100.));
 	zoomBox->Bind(wxEVT_COMBOBOX, &VideoDisplay::SetZoomFromBox, this);
 	zoomBox->Bind(wxEVT_TEXT_ENTER, &VideoDisplay::SetZoomFromBoxText, this);
 
@@ -335,7 +336,7 @@ void VideoDisplay::OnSizeEvent(wxSizeEvent &event) {
 		videoSize = GetClientSize() * scale_factor;
 		PositionVideo();
 		zoomValue = double(viewport_height) / con->project->VideoProvider()->GetHeight();
-		zoomBox->ChangeValue(wxString::Format("%g%%", zoomValue * 100.));
+		zoomBox->ChangeValue(fmt_wx("%g%%", zoomValue * 100.));
 		con->ass->Properties.video_zoom = zoomValue;
 	}
 	else {
@@ -382,7 +383,7 @@ void VideoDisplay::SetZoom(double value) {
 	size_t selIndex = zoomValue / .125 - 1;
 	if (selIndex < zoomBox->GetCount())
 		zoomBox->SetSelection(selIndex);
-	zoomBox->ChangeValue(wxString::Format("%g%%", zoomValue * 100.));
+	zoomBox->ChangeValue(fmt_wx("%g%%", zoomValue * 100.));
 	con->ass->Properties.video_zoom = zoomValue;
 	UpdateSize();
 }
diff --git a/tests/tests/format.cpp b/tests/tests/format.cpp
index 3e8f8d453..551dfc572 100644
--- a/tests/tests/format.cpp
+++ b/tests/tests/format.cpp
@@ -18,6 +18,7 @@
 #include "util.h"
 
 #include <libaegisub/format.h>
+#include <libaegisub/format_path.h>
 
 TEST(lagi_format, s) {
 	EXPECT_EQ("hello", agi::format("%s", "hello"));
@@ -117,3 +118,22 @@ TEST(lagi_format, bad_cast) {
 	EXPECT_THROW(agi::format("%d", "hello"), std::bad_cast);
 	EXPECT_THROW(agi::format("%.*s", "hello", "str"), std::bad_cast);
 }
+
+TEST(lagi_format, wchar_t) {
+	EXPECT_EQ(L"asdf", agi::format(L"%s", L"asdf"));
+	EXPECT_EQ(L"asdf", agi::format(L"%s", "asdf"));
+	EXPECT_EQ("asdf", agi::format("%s", L"asdf"));
+
+	EXPECT_EQ(L"\x2603", agi::format(L"%s", L"\x2603"));
+	EXPECT_EQ(L"\x2603", agi::format(L"%s", "\xE2\x98\x83"));
+	EXPECT_EQ("\xE2\x98\x83", agi::format("%s", L"\x2603"));
+
+	EXPECT_EQ(L"asdf", agi::format(L"%s", std::wstring(L"asdf")));
+	EXPECT_EQ(L"asdf", agi::format(L"%s", std::string("asdf")));
+	EXPECT_EQ("asdf", agi::format("%s", std::wstring(L"asdf")));
+}
+
+TEST(lagi_format, path) {
+	EXPECT_EQ("/usr/bin", agi::format("%s", agi::fs::path("/usr/bin")));
+	EXPECT_EQ(L"/usr/bin", agi::format(L"%s", agi::fs::path("/usr/bin")));
+}