How to change language in Bionic LXDE?

[mlentink]

I have already searched for this in the forums, but can't seem to find an answer:
How do I change the language in Ayufan's Bionic LXDE?
I have already run a

Code:

sudo dpkg-reconfigure locales

and added my locale (dutch, nl-NL), but this has no effect on the menu and panel menus (althought it does in the login screen).

Can I anybody point me to what I am obviously overlooking? 
Thanks!

[hdk]

Ik gebruik Ayufan ubuntu Mate.
In Control Center, Personal, Language support, Install languages:
Dutch toevoegen.
succes

[mlentink]

Ik gebruik Ayufan ubuntu Mate.
In Control Center, Personal, Language support, Install languages:
Dutch toevoegen.
succes

Dank je, maar zo'n control center is er in LXDE niet

[hdk]

Gnome-control-center, system settings?

[mlentink]

Gnome-control-center, system settings?

I'll try, thx