language
again after an update the language settings are not working. I change to Dutch(Nederlands belgie) and i got a mix of english and dutch. It's not the first time after an uopdat that this problem occures.
Opaite Mbohovái (1)
Make sure you have updated the Dutch language pack if you are using an English Firefox version with a Dutch language pack. See "Settings -> Languages"
You can try to clear the startup cache via the "Help -> More Troubleshooting Information" (about:support) page.