Class.hx

class LanguageSelectionState extends FlxFSMState<BattleEngine> {
    var localeButtons:Array<FlxButton>;
    var localeFlags:Array<FlxSprite>;
    var locales:Array<String>;
	var background:FlxSprite;
    var okButton:FlxButton;

    public function new()
    {
        super();
		background = new FlxSprite(0, 0);
		var color = FlxColor.BLACK;
		background.makeGraphic(640, 480, color);
		background.alpha = 0.5;

        localeButtons = [];
        localeFlags = [];
        // Global was already initiated with en-US.
        locales = Global.tongue.locales;
        var i = 0;
        var length:Float = Global.tongue.locales.length;
        var sizeUsed:Float = 50*(length+1);
        var offset:Float= (FlxG.height - sizeUsed)/2;
        for (locale in locales) {
            var locale_text = Global.tongue.getIndexString(IndexString.Language, locale);
            var button  = new FlxButton(0, 50 * i+offset, locale_text);
            button.scale.set(2,2);
            button.updateHitbox();
            button.label.scale.set(2,2);
            button.label.updateHitbox();
            button.x = (FlxG.width - button.width)/2.;
            for(offset in button.labelOffsets)
                offset.y += 4;
            var flag = new FlxSprite(0,0);
            flag.loadGraphic(Global.tongue.getIcon(locale));
            flag.scale.set(2,2);
            flag.updateHitbox();
            flag.setPosition(button.x - flag.width - 2, button.y+8);
            localeButtons.push(button);
            localeFlags.push(flag);
            i++;
        }
        okButton = new FlxButton(0, offset + sizeUsed + offset/2, "OK");
        okButton.scale.set(2,2);
        okButton.updateHitbox();
        okButton.x = (FlxG.width - okButton.width)/2.;
        okButton.label.scale.set(2,2);
        okButton.label.updateHitbox();

        for(offset in okButton.labelOffsets)
            offset.y += 4;

    }
	override public function enter(owner:BattleEngine, fsm:FlxFSM<BattleEngine>):Void
    {
        owner.language_selected = false;
        owner.add(background);
        for(button in localeButtons) {
            button.onDown.callback = function() {
                var index = localeButtons.indexOf(button);
                Global.language = locales[index];
                Global.tongue.init(locales[index]);
                for(button in localeButtons) {
                    var locale_text = Global.tongue.getIndexString(IndexString.Language, Global.tongue.locales[localeButtons.indexOf(button)]);
                    button.text = locale_text;
                }
            }
            owner.add(button);
        }        
        okButton.onUp.callback = function() {
            owner.language_selected = true;
        }

        for(flag in localeFlags) {
            owner.add(flag);
        }
        owner.add(okButton);
    }

	override public function exit(owner:BattleEngine):Void{
        owner.textbox.dismiss();
        owner.remove(background);
        for(button in localeButtons)
            owner.remove(button);
        for(flag in localeFlags)
            owner.remove(flag);
        owner.remove(okButton);


		var tutorial_save = new FlxSave();
		if(tutorial_save.bind("tutorial")) {
            tutorial_save.data.language = Global.language;
            trace("Language saved");
            tutorial_save.close();
		}
		else {
			FlxG.log.error("couldn't open save");
		}

    }
    
}

index.xml

<?xml version="1.0" encoding="utf-8" ?>
<data>
	<file id="battle" value="battle.tsv"/>
	<file id="special_attacks" value="special_attacks.tsv"/>
	<file id="items" value="items.tsv"/>
	<file id="enemies" value="enemies.tsv"/>

	<!--American English-->
	<locale id="en-US" is_default="true" sort="0">	
		<contributors value="Eiyeron"/>
		<ui language="Language" region="Region" accept="OK" />
		<label id="en-US" language="English" region="U.S."/>
		<label id="fr-FR" language="Anglais" region="U.S.A."/>
    </locale>

	<!--French French-->
	<locale id="fr-FR">	
		<contributors value="Eiyeron"/>
		<ui language="Langage" region="Région" accept="OK" />
		<label id="en-US" language="French" region="France"/>
		<label id="fr-FR" language="Français" region="France"/>
    </locale>
</data>

Would be there a way to get a specific Language tag from a given other language, something like

getIndexString(index:String, id:String, locale:String);

Because I can't make tjhe menu change the button labels without having to reload FireTongue, unless it's the intended behaviour.

(SOrry, I'm not so clever)

Edit: I'm trying to edit the labels directly on a call back, I'd like to reproduce that logic without having to call init.

           button.onDown.callback = function() {
                var index = localeButtons.indexOf(button);
                currentLocale = locales[index];

                // Global.language = locales[index];
                Global.tongue.init(locales[index]);
                for(butt in localeButtons) {
                    var buttonLocale = Global.tongue.locales[localeButtons.indexOf(butt)];

                    var locale_text = 
                    Global.tongue.getIndexString(IndexString.LanguageBilingual, buttonLocale)
                    ;
                    butt.text = locale_text;
                }
            }