Simple and easy. Works as expected.

Works like a charm! Thank you!

El único problema es que no funciona en modo privado.
Una sugerencia sería un botón de "Aceptar" al lado del cuadro de texto.

I have tried everything I can think of for changing the accept-language of Firefox, but it seems to be stuck on en-GB. I've changed the locale of my system to en-US but Firefox still sends out en-GB. I tried your addon to fix it and it still wont change. I will be willing to give higher marks if you can show that your addon is fine and that it's something else.

Yeah your addon is just fine I think. I'm blaming this one on MOZILLA FF. the addon wasn't changing anything in the accept-language field until I changed "en-US,en" to just "en-US"

FF is kinda shoddy like that.

Работет. Гут

Exactly what I was looking for.

It works and I can finally access a specific website in the language I require. I would like an interface which lets me set different locales for different websites.

However, it is sufficient for my rare need to access this website and it helped me a lot. Thank you.

Wow! It's just what I was looking for. Thanks!

very handy. Hotkeys would be welcome though!

This works well, on some tabs. On other tabs, it doesn't change the Accept-Language header at all. Maybe there is a e10s-multi incompatibility?

Works as advertised in Firefox 53.0 after the author pushed a bug fix. See https://github.com/callahad/quick-accept-language-switcher/issues/4.

Presentation for handling things like "q=0" (disallowed languages), multiple accepted languages, and invalid header strings could be improved, but those issues are merely cosmetic.

Firebug still shows Accept-Language
en-US, while I set "fr". FF52. Seemed simple and right tool, but does not work.

And it is open source :-)

As already mentioned dropdown of values history will be great. Also it would be great to set specific values for specific domains.

And ability to add presets to the options for needed combinations. Use that presets in the drop-down menu.