Actually the best way is to download Firefox in the language interface you want to use from this website. https://www.mozilla.org/en-US/firefox/all/

I hope this helps.

If we can be of further assistance please let us know!

irina.saiz said

Is there any setting abailable in the menu, that can be used in order to change menu language? I used this https://support.mozilla.org/en-US/questions/1018686 to get my menu to be in English, but having an option in the menu would be easier.

Do you want to use multiple languages?

If you want to do this then best would be to install the en-US version and additional language packs for the other languages.

• https://addons.mozilla.org/firefox/language-tools/

If you only need one language then install this version. You can find the full version of the current Firefox release (57.0) in all languages and all operating systems here:

• https://www.mozilla.org/en-US/firefox/all/

Note the there is also a command line switch to start Firefox with a specific locale.

You can create a desktop shortcut with the "-UILocale xx-xx" switch appended to the command line to start Firefox with a specific locale.

• https://developer.mozilla.org/Command_Line_Options