Comment # 1 on bug 977139 from Kristyna Streitova

(In reply to Christian Boltz from comment #0)
> I can reproduce this error by running   SET lc_messages = 'de_DE';   in the
> 'mysql' commandline client.
> 

I tried to reproduce it in the 'mysql' command line client as you wrote
(without phpMyAdmin). But it seems that it works fine for me (openSUSE
Tumbleweed). 

<snip>
MariaDB [(none)]> SET lc_messages='de_DE';
Query OK, 0 rows affected (0.00 sec)
</snip>


So I would say that the problem is somewhere else. Firstly, you can check if
the error message directory/file is present. Default location for the language
files is '/usr/share/mariadb/<language>' directory. You should see 'german'
directory there. If you changed the directory storing the error messages by
'lc_messages_dir' system variable, please check the defined directory.

For more information please read [1] or [2].


[1] https://mariadb.com/kb/en/mariadb/setting-the-language-for-error-messages/
[2] https://dev.mysql.com/doc/refman/5.6/en/error-message-language.html