Solved
although logged in, the forum appears in English (from this afternoon).
The homepage of GeoGebra and GGTube appear in dutch, according to the account settings, so it's just the forum.
The same problem 
although logged in, the forum appears in English (from this afternoon).
The homepage of GeoGebra and GGTube appear in dutch, according to the account settings, so it's just the forum.
Mr Forum is on holiday.
I've told him about this issue. He says he'll be back on Monday. In the meanwhile also the other developers can see my message, so I don't know if a kind volunteer (Zbynek ha ha ha) will have a look at this before.
Have a nice day :)
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