Language dont work

Hi all,

trying to set up a new wordpress bases website. I’ve installed a new version of wordpress, all is working. Now I tried to localise it by using the dutch language file. I’ve uploaded into the right directory and changen the wp-config.php file, but nothing’s changed. Except for my own text, not a dutch word to be found. Anyone know what could be wrong?
See: https://www.tebubo.nl