how to set default language for facebook in webview for flutter_facebook_login plugin

Question

Im using flutter_facebook_login plugin https://pub.dev/packages/flutter_facebook_login

Future<Null> _facebookLogin() async {

facebookSignIn.loginBehavior = FacebookLoginBehavior.webViewOnly;
FacebookLoginResult result = await facebookSignIn.logIn([
  'email',
  'instagram_basic',
  'pages_show_list',
  'pages_read_engagement'
]);

switch (result.status) {
  case FacebookLoginStatus.loggedIn:
    accessToken = result.accessToken;
    _loginAsNewUser(accessToken.token);
    break;
  case FacebookLoginStatus.cancelledByUser:
    Navigator.of(context).pop();
    _auth.signOut();

    break;
  case FacebookLoginStatus.error:
    simplestDialogBox(
        context, 'An error Occured! Please try after some time.', () {
      Navigator.of(context).pop();
    });
    _auth.signOut();
    await _logOut();
    break;
}
}

Here I'm using web View for login. So how to set default language as English for the login page? I sometimes get Marathi, sometimes Hindi, which is local language. If i were to use use native view or browser, then the language will depend upon user preferences, but how to use default language EN in web View.