Idk which models you refer to, but I tested a bunch recently, and they performed well on Dutch. Only the smallest, such as qwen 3.6 27B, made up words and switched languages.

I don't understand this. Even if that were true (and it isn't in my experience), a model that is trained on a Dutch corpus and arguably "knows Dutch well" but has the reasoning and comprehension abilities of a three year old is useless in any case. I'd rather use a model that can only speak English and put an automatic translator around it.