How to disable language selection for customers

[Sascha Loeffler]

Hi, 

we want to show our service desk portal only in english (default) and users should not be able to change there langauge preferences. 
I tried to disable the languages like german in the project settings but that does not affect to the language picklist. 

Is there any possibility for that? 

Thanks in advance

[M Amine]

The language picklist is not configurable.