Language and language support is up to the writers of those programs. What you could do is offer to translate for them. Contact their support.

Apparently most addons with localization will check firefox's language (maybe general.useragent.locale?) and show that translated string. My question was is there a way to make firefox tell the addons to use a different language without having to change the browser's language? somthing like extensions.language

Not that I have heard. Some add-ons do have a language choice, however. Perhaps this site can help; https://discourse.mozilla-community.org/c/add-ons

Does it has effect when you set general.useragent.locale to en-US despite having a different locale installed?

Firefox determines automatically what locale to use.

See also:

• intl.locale.matchOS

Whoa that did the trick. Changed "general.useragent.locale" to en-us WITHOUT installing the English language pack. Browser stays non-English but addons are in English now. Firefox startpage is also in English but not an issue. Other places may show up in English too but I dont really care now.

Why didn't I thought of this earlier... Thank you very much!

Changing "general.useragent.locale" is no longer working for the past few versions.

Anyone have any ideas to change ui language for addons?

kzyswd said

Im using a non-English version of firefox. Some addons that have translation is only partially translated into my language, and the translation isnt good either. I just want it to be in English but the app devs said they cannot set the language strings independent of what is set in my browser. Is there any way I can tell the addons to use English, without having to change firefox's language into English? Maybe in about:config?

Off Topic here but if you want a Browser that will do it automatically when set it is Chrome. I use it for Foreign language pages and online order sites. This gives faster translation if you need quicker. FF currently now has no such Translation built in. So if you want Translated pages your best to use Chrome until FF develops a Translation engine into their Browser.

WestEnd said

Off Topic here but if you want a Browser that will do it automatically when set it is Chrome. I use it for Foreign language pages and online order sites. This gives faster translation if you need quicker. FF currently now has no such Translation built in. So if you want Translated pages your best to use Chrome until FF develops a Translation engine into their Browser.

Im not looking for any web translation. Addons are localized into several languages and currently its using the same language as the installed firefox. Just a few months ago I could set general.useragent.locale = en-us on my non-English FF and addons would show up in English. It doesn't anymore and Im looking for other ways to make it English again.

What Firefox version do you currently use?

In Firefox 59+ you need to set/create this string pref to set the locale.

• intl.locale.requested = "en-US"

cor-el said

What Firefox version do you currently use? In Firefox 59+ you need to set/create this string pref to set the locale.

• intl.locale.requested = "en-US"

It's Firefox 59. I did try that but its only useful after installing the language pack(in this case EN lang pack) and it changes the entire browser UI into English. Basically the same as installing English version of FF.