Jak tłumaczyć kod języka angielskiego na wiele języków w pliku .dart

import 'package:i18n_extension/i18n_extension.dart';
extension Localization on String {
  //en,fr,es,de
  static var _t = Translations("en") +
      {
        "en": "Type here",
		"te": "",
		"ta": "", 
		"ml": "", 
		"kn": "", 
		"hi": ""
      } +
      {
        "en": "Welcome",
		"te": "",
		"ta": "", 
		"ml": "", 
		"kn": "", 
		"hi": ""
      } +
      {
        "en": "Something wrong",
		"te": "",
		"ta": "", 
		"ml": "", 
		"kn": "", 
		"hi": ""
      } +
      {
        "en": "New Message from",
		"te": "",
		"ta": "", 
		"ml": "", 
		"kn": "", 
		"hi": ""
      };
  String get i18n => localize(this, _t);
  String fill(List<Object> params) => localizeFill(this, params);
}