I imagine they would just teach it in English. I believe it's pretty standard for Western European students to learn English fluently. Maybe dual language? OMSCS gets a fair number of foreign students from around the world and only teaches in English AFAIK.

Dutch master's are all English for a while now. You don't get the same subsidies as EU residents, though, but it's also no more expensive than this online business and you get to have an actual classroom (for many that's a plus).