[theme-reviewers] Adding language files

[Mats Birch]

A quick question.

If a theme gets a new translation, what is the preferred way to bundle 
it with the theme?
It seems like overkill to release it as a new version just for that, and 
have all users update.
And since rather few want the translation, I guess that all the others 
will be disappointed (I know I would be).
Is there another way?

Thanks.