WebGUI-Change language

I installed FreePBX on my Raspberry Pi. I want change language in WebGUI to Spanish (for example) but it isn’t possible. When i clicked to other language the page was refreshed but language wasn’t changed.

I tried this methods:
…But it wasn’t helped me.

If you don’t know how to fix this problem I have next question…Where is saved the default language (en_US) file? I can’t find it in “/var/www/html/admin/i18n”.

Please, help me with this problem. Thank you.

P.S.: I’m sorry for my English, I’m from Czech.

OK, I fixed it. In my PHP wasn’t install GetText and after install I must enabled languages in raspi-config.