“But I guess the Cornish would be a matter that is in a way inseparable from race/heritage”
Cornish is a language spoken in The Sims 2. It is most often heard when waffles made of corn are painted in dodgy locks. In addition, it is a home language in Simmish communitites. In other commercial contexts, the Simmish people speak some kind of pidgin so that they can trade with Sweden for Swedish fish.