How do I make Lumen to use default validation messages?

I have a standard folder for error messages in Lumen which is similar to Laravel. The problem is that the messages from there are not used. How can I make Lumen to format messages using my translations?

Right now when I dump $validator->errors() it does not format the messages.

MessageBag {#223
  #messages: array:4 [
    "surname" => array:1 [
      0 => "validation.required"
    ]
    "mobile" => array:1 [
      0 => "validation.required"
    ]
    "password" => array:1 [
      0 => "validation.min.string"
    ]
    "email" => array:1 [
      0 => "validation.email"
    ]
  ]
  #format: ":message"
}