I haven’t used it myself, but someone elsewhere in the comments linked this extension: https://addons.mozilla.org/en-US/firefox/addon/accept-language-per-site/

I haven’t used it myself, but someone elsewhere in the comments linked this extension: https://addons.mozilla.org/en-US/firefox/addon/accept-language-per-site/ https://addons.mozilla.org/en-US/firefox/addon/accept-langua...