I used to work with Firefox in French but decided to change to all English. For some reason, Firefox is having none of it. At best I get it in a mix of French and English and it's really awkward to read. What I know: - Making a new profile on the same machine solves it, but only for that new profile - Alt-menu and the main menu are affected, but about: pages are all in English - Some sections of the main menu are in English in the middle of the French: The button to open Pocket, the button to open my screenshots, the button for the content blocker, and a seemingly random bunch of the dev tools' names What I tried (with little success): - Reinstalling, making sure I took an en-US download - Disabling matchOS in about:config (my operating system is in English anyways) - Setting my requested language to "en" or "en-US" in about:config - Language packs, remove all but English (tried removing English too, for experimental purposes) - Checked the Firefox language settings, there's only English in the list - Same as above for website language settings PS: had trouble uploading screenshots to the support page so here's an Imgur album https://imgur.com/a/65NV7kO