Tarock and Tarot is not the same thing and I wouldn't like to mix them up.
taROH is how I say it. I admit that tarrow sounded a bit, um, weird to me when I heard it first on Youtube. Marcus Katz says taROH in his videos, and I was not aware of tarrow ;-) .
Btw, Köln and Cologne are both variations of the official Latin name, Colonia, given to the village when the Romans re-founded it as city. Natives call it Kölle anyway.
Important cities have different names in different languages, that's normal for Europeans, and it reflects the city´s international importance. Or, as already mentioned, in the case of Belgian or Alsacian places, the fact that they belonged to different countries at different times or that the country is multi-lingual.
If you think it's imposing your language on the people of Cologne to call their city by its English or French name, you'll have to call Germany Deutschland from now :-D