In-game check Setup -> Game Options. At the very bottom you will see options for Text and Voice languages. You will see that some things, but not all, are already supported.
If you wanted to take the time, it is possible to add localization support to many areas of MB2 without the help of developers. Adding an identifier to a where an old string was with @STRING_REFERENCE_NAME_HERE style then creating or updating existing string files with the correct identifier and old text.
I know the IN-Game options, and as you said, there is vital information that isn't supported, the "libraries" for example, or mb2 guides. :c
Ill try to contact someone near the developers, in some specific topics of the forums, but.. if mb2 continues without updates, it will die soon.. there is other jka mods that are very fun, but this one became very realistic ("""logic""" battles for me, ofc there is other games) compared to them.
Helping mb2 to survive its in the hands of the community and the disposition of the developers.