I am not able to check/uncheck the checkbox(flutter)

This is the minimum code I am not able to check/uncheck the checkbox. What to do??

         Row(
           children:<Widget>[
           Text("English"),
           Checkbox(
            checkColor: Theme.of(context).primaryColor,
            value:false,
            onChanged: (bool value) {
              setState(() {
                if(value==true) {
                  lang.languages = "English";
                  print(value);
                }
              });
            },
          )])