When you open a file, there is no info about different language "versions" of the document, when text is more than in one language available.

My proposal(s):
1. When opening a multi-language file, a popup-dialog appears "This document is available in the following languages: lang1, lang2, ...".
2. or, a more descreet version: in the menue bar there's a "choose doc language" list. When only one language is detected, this list is greyed. When more languages are dedected you can choose your language in this list. The entry in the context menue ist still needed to make new language "versions", which are not in this list.