Some non-English websites show a dumbed-down/outdated English version to all visitors whose browsers identifies them as English readers. I usually browse in English but I can read more languages, so I would like to have an easy way to say "Consider me as a Japanese person" for instance.


  • Sets the ACCEPT_LANGUAGE HTTP header to the language of my choice, in all requests sent within that tab.
  • Does not change the Firefox menus/etc. Only the content of the web page should use the language, not Firefox itself.
  • No need to download "language packs".
  • Free, ideally open source.

I tried:

  • Could you list some websites that exhibit this issue?
    – user3169
    Commented Feb 24, 2017 at 7:00
  • @user3169: The Firefox add-ons site redirects based on the Accept-Language header, so this could be used for testing. Example: https://addons.mozilla.org/firefox/addon/tablang/ -- if you have a higher value for German than English, you will get redirected to https://addons.mozilla.org/de/firefox/addon/tablang/, and if English is higher, to https://addons.mozilla.org/en-US/firefox/addon/tablang/.
    – unor
    Commented Feb 24, 2017 at 9:16

1 Answer 1


I'm using Quick Locale Switcher for that, and am quite satisfied with it. This addon fits all your requirements, also the implicit one: As below screenshots show, you can configure for which URLs a specific language should be used.

menu config autoswitch
Screenshots: Menu, config, config for auto-switch per URL (click images for larger variants)

Works fine for me here, though it hasn't been updated in a while. There's a somehow more recent "spin-off" by the name Quick Locale Switcher 2, but that still carries a very low version number (0.0.1) and obviously is not yet complete (e.g. auto-switching currently does not work). Still worth keeping an eye on in case it catches up – one never knows what time Mozilla decides to drop some compatibility…

Update: While the former is no longer available at AMO, the latter still is. I've updated its URL with this edit. It's now at v0.1, but wasn't updated since 10/2018.

  • Drawbacks: Last updated in 2013, and some reviews mention it contains spyware.
    – Nicolas Raoul
    Commented Feb 27, 2017 at 3:17
  • I just tried the spin-off. Even after I choose German, whatismybrowser.com/detect/… still says I am using en-US,en;q=0.5. I restarted several times after installing.
    – Nicolas Raoul
    Commented Feb 27, 2017 at 3:26
  • @NicolasRaoul I've mentioned it has not been updated in a while. But it works fine for me, so I still can recommend it :) I've never tried the spin-off as a) I'm happy with the original and b) the spin-off still seems to be in Alpha or Beta state (v0.0.1). I've just mentioned it as one day it might be "mature", so then it should be known to exist :)
    – Izzy
    Commented Feb 27, 2017 at 7:47

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