Multi-Language application with manual language choosing

Question

I have an app and in the first interface I need to choose one language.

I'm only using two lang.

And I want the text on the login to to be in that lang I choosed.

Should I use Localization?

This is my main.dart

    void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: SplashScreen(),
      routes :{
        'lang' : (context) => Languagepage(),
        'fr_version' :(context) => LoginFormfrancais(),
        'ar_version' :(context) => LoginFormarabic(),

      },
    );
  }
 }

and this is the languages page where to choose: I only have two language:

  class _LanguagepageState extends State<Languagepage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        backgroundColor: Color.fromARGB(255, 4, 24, 54),
        body: Center(
            child: Column(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                children: <Widget>[
              ElevatedButton(
                style: ElevatedButton.styleFrom(
                  primary: Color.fromARGB(255, 228, 116, 42),
                  onPrimary: Color.fromARGB(255, 4, 24, 54),
                  shadowColor: Colors.greenAccent,
                  elevation: 3,
                  shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(32.0)),
                  minimumSize: Size(900, 100), //////// HERE
                ),
                onPressed: () {
                  Navigator.pushNamed(context, 'fr_version');
                },
                child: Text('FRANCAIS'),
              ),
              ElevatedButton(
                style: ElevatedButton.styleFrom(
                  primary: Color.fromARGB(255, 228, 116, 42),
                  onPrimary: Color.fromARGB(255, 4, 24, 54),
                  shadowColor: Colors.greenAccent,
                  elevation: 3,
                  shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(32.0)),
                  minimumSize: Size(900, 100), //////// HERE
                ),
                onPressed: () {
                 Navigator.pushNamed(context, 'ar_version');
                },
                child: Text('العربية'),
              ),
            ])));
  }
}