你寫的這個messages方法表單驗證類里面才使用的吧，如果在在控制器做驗證這樣寫：

public function registter(Request $request){
    $messages = [
        'email.required' => '郵箱不能為空',
        'password.required' => '密碼不能為空',
        'password2.required' => '確認密碼不能為空',
    ];
    $validator = Validator::make($request->all(),[
        'email' => 'required|email',
        'password' => 'required',
        'password2' => 'required',
    ],$messages);
    $errors = $validator->errors(); // 輸出的錯誤，自己打印看下
    if ($validator->fails()){
         return response()->json([
             'success' => false,
             'errors' =>  $errors
         ]);
    }
}