how force locale set in user settings overrule locale detected by browser - laravel

Users of my app can set up their preferred locale in their settings panel. In my case it is pl. However, when I am using the app as a logged user on a browser which preference of locales does not contain pl or has it below en, I see english translations.

My problem: how make the browser observe the locale set by user? Or... how to force the app to switch to the user-preferred locale?

via Chebli Mohamed