It just stopped at http://***/admin.php?languages/
It didn't get to the rebuilding caches and templates stuff. However, now it's working properly. I will explain how to get an error if I manage to execute it on our board.
yep. these languages contains all phrases (about 2885). part of phrases are in russian.
so if i want to delete these languages from system, i must manually delete records from tables prefixed "xf_phrases" and after that i can delete language.