laravel change validation default message from front side

Use Validator class

use Illuminate\Support\Facades\Validator;

$rules = [
    'name' => 'required',
    'email' => 'required|email,
];

$messages = [
    'name.required' => 'The :attribute is required',
    'email.required' => 'The :attribute is required',
    'email.email' => 'The :attribute is not valid',
];

$validator = Validator::make($request->all(), $rules, $messages);

if ($validator->fails()) {
    return Redirect::back()->withErrors($validator)->withInput();
} else {
  `enter code here`
}