German dialect in Texas is one of a kind, and dying out

[Schroeder]

Then it must be a coincidence. The Dutch van and the German von are separate words that are separated by a space from the rest of the family name.

[Sailor Steve]

Originally Posted by Schroeder

Then it must be a coincidence.

Not coincidence, but evolution. Names get changed for a variety of reasons. My family name was Brodfeld. The were part of the Saxon invasions in the post-Roman days. By the 10th century they were solidly English and the name had become Bradfield. It happens all the time.

The Canadian city of Vancouver is named for George Vancouver, the Royal Navy captain who charted that region. His family name is believed to have originally been either van Coevorden or van Couwen. Vancouver himself believed the former to be correct, but both names were originally two words.