Hi,
We encountered an issue with the "Lock language versions". I understand that it locks the language version so they cannot be edited.
We have one solution with a number of languages with different content in the different language versions. For some reasons the "Lock language versions" was checked on some master pages. And when the user updated the master page the content from that page got copied to all the language versions.
I don't know if that is by design or a bug. If it's by deisgn there should be, in my opinion, some kind of warning if the system is going to overwrite data.
Regards / Aki