I know that deep in the wish list for Labdoo there is a task to redesign the text and usage of notification mails. But maybe there is an easier way to solve the need. Remember the mail from today (24.04.) from Kenya complaining about receiving too many mails? It was mainly because he received German mails.
How about leaving the text and notification mails as they are (maybe only translate the status text in the future), but adding a selection box for the user language, when adding a new notification e-mail? For registered users our systems knows, which language they selected. But for manual added emails this is unknown. Default could stay English, but via the selection box (same as selecting user language for GUI) for each email the language can be assigned. If the email text is not available for the selected language (e.g. because in translation process) default would be English.
Maybe this is easier to solve than reorganising the complete notification mails and text?