i'm sure that's no configuration issues of settings.py.
Here is a detailed description of the error(BUG).
On the login page of iRedAdmin Pro 1.8.0 is the standard language is 'en_US'.
OK ... That's what I want...
1 - The Combobox shows russian NOT en_US
2 - If i choose a different language like German (Deutsch) or any other
the url will be added to this option but the combobox
immediately jumps back back to russian.
3 - ok i ignore the combobox(russian) and login with the German option(URL).
the complete iRedMailAdmin UI is still on standard language 'en_US'.
By the way,
to validate the error I have the 1.7.0 version enabled. (ln -s iRedAdmin-Pro-MySQL-1.7.0 iredadmin)
the language in the version 1.7.0 was working properly!