【FuelPHPの使い方】バリデーションチェックのエラーメッセージを日本語化する方法

return array(
'required' => 'The field :label is required and must contain a value.',
'min_length' => 'The field :label has to contain at least :param:1 characters.',
'max_length' => 'The field :label may not contain more than :param:1 characters.',
'exact_length' => 'The field :label must contain exactly :param:1 characters.',
'match_value' => 'The field :label must contain the value :param:1.',
'match_pattern' => 'The field :label must match the pattern :param:1.',
'match_field' => 'The field :label must match the field :param:1.',
'valid_email' => 'The field :label must contain a valid email address.',
'valid_emails' => 'The field :label must contain a list of valid email addresses.',
'valid_url' => 'The field :label must contain a valid URL.',
'valid_ip' => 'The field :label must contain a valid IP address.',
'numeric_min' => 'The minimum numeric value of :label must be :param:1',
'numeric_max' => 'The maximum numeric value of :label must be :param:1',
'numeric_between' => 'The field :label must contain a numeric value between :param:1 and :param:2',
'valid_string' => 'The valid string rule :rule(:param:1) failed for field :label',
'required_with' => 'The field :label must contain a value if :param:1 contains a value.',
'valid_date' => 'The field :label must contain a valid formatted date.',
);

/**
* The default language.
*/
'language' => 'ja', // jaに変更
'language_fallback' => 'en',