diff --git a/backends/platform/ios7/ios7_osys_misc.mm b/backends/platform/ios7/ios7_osys_misc.mm
index f0e6067ec24..b4780577c10 100644
--- a/backends/platform/ios7/ios7_osys_misc.mm
+++ b/backends/platform/ios7/ios7_osys_misc.mm
@@ -39,10 +39,14 @@ static inline void execute_on_main_thread_async(void (^block)(void)) {
 }
 
 Common::String OSystem_iOS7::getSystemLanguage() const {
-	NSString *locale = [[NSLocale currentLocale] localeIdentifier];
-	if (locale == nil)
+	NSString *language = [[NSLocale preferredLanguages] firstObject];
+	if (language == nil)
 		return Common::String();
-	return Common::String([locale cStringUsingEncoding:NSISOLatin1StringEncoding]);
+	Common::String lang([language cStringUsingEncoding:NSISOLatin1StringEncoding]);
+	// Depending on the iOS version this may use an underscore (e.g. en_US) or a
+	// dash (en-US). Make sure we always return one with an underscore.
+	Common::replace(lang, "-", "_");
+	return lang;
 }
 
 bool OSystem_iOS7::hasTextInClipboard() {
diff --git a/backends/platform/sdl/sdl.cpp b/backends/platform/sdl/sdl.cpp
index 386c8a867f6..c9349dfca46 100644
--- a/backends/platform/sdl/sdl.cpp
+++ b/backends/platform/sdl/sdl.cpp
@@ -565,16 +565,17 @@ Common::String OSystem_SDL::getSystemLanguage() const {
 	// Detect the language from the locale
 	if (locale.empty()) {
 		return BaseBackend::getSystemLanguage();
+	} else if (locale == "C" || locale == "POSIX") {
+		return "en_US";
 	} else {
 		int length = 0;
 
-		// Strip out additional information, like
-		// ".UTF-8" or the like. We do this, since
-		// our translation languages are usually
-		// specified without any charset information.
+		// Assume the locale is in the form language[_territory[.codeset]][@modifier].
+		// On macOS the format is different (it looks like C/UTF-8/C/C/C/C), but we
+		// have a different implementation of getSystemLanguage for macOS anyway, so
+		// we don't have to handle it here.
+		// Strip out additional information, like ".UTF-8" or the like.
 		for (int size = locale.size(); length < size; ++length) {
-			// TODO: Check whether "@" should really be checked
-			// here.
 			if (locale[length] == '.' || locale[length] == ' ' || locale[length] == '@')
 				break;
 		}
diff --git a/common/system.h b/common/system.h
index 26c6963a443..4ef6825d097 100644
--- a/common/system.h
+++ b/common/system.h
@@ -1807,16 +1807,17 @@ public:
 	virtual bool openUrl(const Common::String &url) {return false; }
 
 	/**
-	 * Return the locale of the system.
+	 * Return the language of the system.
 	 *
-	 * This returns the currently set locale of the system on which
+	 * This returns the currently set language of the system on which
 	 * ScummVM is run.
 	 *
-	 * The format of the locale is language_country. These should match
-	 * the POSIX locale values.
+	 * The format is an ISO 639 language code, optionally followed by an ISO 3166-1 country code
+	 * in the form language_country.
 	 *
 	 * For information about POSIX locales, see the following link:
-	 * https://en.wikipedia.org/wiki/Locale_(computer_software)#POSIX_platforms
+	 * https://en.wikipedia.org/wiki/ISO_639
+	 * https://en.wikipedia.org/wiki/ISO_3166-1
 	 *
 	 * The default implementation returns "en_US".
 	 *