typo fix

docs/guide/i18n.md

@@ -357,7 +357,7 @@ class Module extends \yii\base\Module
 ```
 
 In the example above we are using wildcard for matching and then filtering each category per needed file. Instead of using `fileMap` you can simply
-use convention of category mapping to the same named file and use `Module::t('validation', 'your custom validation method')` or `Module::t('form', 'some form label')` directly.
+use convention of category mapping to the same named file and use `Module::t('validation', 'your custom validation message')` or `Module::t('form', 'some form label')` directly.
 
 ###Translating widgets messages