I bumped on this issue while configuring dektrium\user module. There is a ‘mailer’ section where one may provide standard e-mail subjects for various messages sent by the module (e.g. registration confirmation message, password recovery message, etc.).
Obviously - these message subjects should be localized - so are messages themselves!
But… I found translation module does not work on application config file at all (even while bootstraped).
Simply speaking, this:
'mailer' => [ 'recoverySubject' => Yii::t('app', 'Password recovery'), ]
does not work and non-translated text is being passed to SwiftMail. Message subject remains unlocalized.
Any idea how to overcome this nasty issue?