I've just received a talk page notification from fo.wiki even though my interface language is not in English there.
Compare:
- https://translatewiki.net/wiki/Special:Translations/MediaWiki:Notification-edit-talk-page-email-subject2 (106)
- https://translatewiki.net/wiki/Special:Translations/MediaWiki:Enotif_body (175)
It's a remarkable waste to use English in email notifications, which are the only way we reach out to many of our less active registered users.