As we know that Firefox is available in so many languages in addition to the default English language. You can download Firefox in any language from this page. The problem with Firefox downloaded in different languages was that only one language could be installed at a time. The second biggest problem was that the language packs of Firefox had to be updated for each and every release of Firefox. This was quite a hard work for the people who were maintaining the language packs.
There was yet another problem that the users had to download and install the correct language pack that was compatible with their version of Firefox. If the wrong language pack was selected and installed, it would not work. So this feature of language packs auto-update feature remained a feature request for quite some time.
Now Mozilla has made the language packs feature available to all the users. Now whenever the user updates his installation of Firefox, the language pack he has installed will also be auto-updated with the most recent and compatible language pack. This means that the users will not run into compatibility issues any more.
If you go to Mozilla language tools section, you will see two downloads for each language, dictionary and language pack. The dictionary will add auto-correct feature for that particular language in Firefox while the language pack will change the language of Firefox completely including menus, toolbars, help section etc.
Now you can also change the language of Firefox on the fly. For this, you will have to follow the instructions below:
Go to the awesome bar and write about:config.
Pressing enter will take you to the advanced Firefox configuration.
Please note that you will be given a warning that changing the advanced settings can be harmful to your installation of Firefox. Just press the “I’ll be careful, promise” button.
Search for general.useragent.locale and change its value to the locale or language abbreviation you want to convert to.
You will need to restart the browser in order for the new selected language to take effect.
An easier solution would be to install Quick Locale Switcher Firefox add-on. This will give you an additional menu under Tools menu from where you can select any language that is installed in your Firefox browser.