Firefox has a list of built-in languages that are used to set the HTTP_ACCEPT_LANGUAGE header. How do I add a custom one that's not on the list?
3 Answers
Is this what you're looking for?
Tools -> Options -> Content -> Languages -> Select a language to add
It's from a similar post.
EDIT:
As far as I can tell, this GUI option just changes the preference "intl.accept_languages" in about:config. You could edit this yourself to change it to a custom value. I'm not sure if you can put language files somewhere to get a custom language to work or not.
You can use about:config to edit the list of language codes:
Enter about:config into address field, find the setting intl.accept_languages. Its value is the list of language codes to send as Accept-Language HTTP header. The list is comma-separated in descending priority. You can enter any code you like; the codes will even be displayed in the standard pref dialog (see mouche's answer), where you can delete them later (just not add them).
As an aside: Why do you need this? I have never encountered a website that supports more than the (extensive) set of standard tags as defined in ISO-639. Which special tags do you want to use, and why?
Firefox has a section on their website where you can download and add custom languages to your Firefox:
- 717