Use IETF standard language tags for locale names

build/data/obs-studio/locale.ini

-[en]
+[en-US]
 Name=English
 
-[ru]
+[ru-RU]
 Name=Русский
 
-[fi]
+[fi-FI]
 Name=Finnish
 
-[it]
+[it-IT]
 Name=Italian
 
-[ja]
+[ja-JP]
 Name=日本語
 
-[de]
+[de-DE]
 Name=Deutsch
 

obs/obs-app.cpp

@@ -97,7 +97,7 @@ static void do_log(int log_level, const char *msg, va_list args, void *param)
 
 bool OBSApp::InitGlobalConfigDefaults()
 {
-	config_set_default_string(globalConfig, "General", "Language", "en");
+	config_set_default_string(globalConfig, "General", "Language", "en-US");
 	config_set_default_uint(globalConfig, "General", "MaxLogs", 10);
 
 #if _WIN32
@@ -156,7 +156,7 @@ bool OBSApp::InitGlobalConfig()
 	return InitGlobalConfigDefaults();
 }
 
-#define DEFAULT_LANG "en"
+#define DEFAULT_LANG "en-US"
 
 bool OBSApp::InitLocale()
 {

test/win/test.cpp

@@ -71,7 +71,7 @@ static void CreateOBS(HWND hwnd)
 	RECT rc;
 	GetClientRect(hwnd, &rc);
 
-	if (!obs_startup("en"))
+	if (!obs_startup("en-US"))
 		throw "Couldn't create OBS";
 
 	struct obs_video_info ovi;