String language = "ru-en";
    String langForAn= "en";

sw.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

                if(!isChecked){
                    language = "en-ru";
                    langForAn="ru";
                }
                Log.d("Используемый язык",language);

            }
        });