Please do the following:
Via your terminal, run php flarum info at the flarum folder and verify that flarum/flarum-ext-english is installed.
Remove the .js files from your assets folder.
Open your admin panel, navigate to the extensions tab and uncheck the box under the English extension (the Union Jack flag). Then re-check it.
Hard-refresh your browser on both the Admin page and your forum home page.
If that doesn't fix it, please return here.
