Has Siri the Dutch language on the homepod ?

Unfortunately it isn't as simple as that. Siri on HomePod is supported in a much smaller range of countries and languages than Siri on iPhone. I don't know exactly why, but it may have to do with the integration of support for services such as local news, weather and radio.

tt2

I don't believe so. Unless Apple have started selling HomePod in Dutch stores then it is safe to assume that it is not yet supported in the Netherlands.

tt2