I fixed the problem after 4hours ^^ .
How to fix it ?
You must need tables languages: ow_base_language, ow_base_language_key, ow_base_language_prefix, ow_base_language_value .
You reinstall oxwall.
You delete the tables: ow_base_language, ow_base_language_key, ow_base_language_prefix, ow_base_language_value
After you import the tables.
Go to admin language. Clone your lost language.
Rename the language like test or 123. Delete the old language lost. Rename test with his real name.