Can't install language pack

I’m now using version 57 and I can’t install languages packs.
I go to languages packs page, I click in install, no error is indicated but I try no access to a new language only my native language is available.
There isn’t any reference to installed languages packs, which are shown (without any error) on addon page.
Anyone can help me?

Installing a language pack doesn’t immediately change the language in the Firefox UI. You need to change a preference to make it work:

https://support.mozilla.org/en-US/kb/use-firefox-interface-other-languages-language-pack

Hi Jorge,

Thanks for your reply.
My problem is that after installing the language packages when I click right botton in a text box only my native language appears.
Although if I check the add-ons on settings other languages are installed…

To get spell checking support you’d have to install the dictionary and not the language pack from https://addons.mozilla.org/en-US/firefox/language-tools/

Language packs are user interface texts, dictionaries are the spell checking.

Hello,

Thanks a lot for your help.

You are 100% correct.