My Dad's parents were born and raised in Czechoslovakia, and even though he was born in the US, he still often peppered his conversation with Czech words and phrases from his youth. For example, the
lamb-shaped butter we always bought at Easter he called by its Czech name ("baranya" is the closest I can get in English spelling). But he never referred to sour cream as anything other than sour cream.
Interestingly enough, years ago I was the host of a small US-based fan club convention that had attracted a few visitors from the UK. One of the dessert items in the buffet line was Strawberries Romanoff, which included a healthy serving of sour cream in the recipe. One our British visitors approached me after taking a second helping of the dessert and asked me what type of cream was mixed with the strawberries, as it was delicious and he'd never tasted anything quite like it. "It's sour cream," I replied. He almost dropped his dessert dish in horror. "You mean it's spoilt?!" I assured him that it was safe to eat and was a common ingredient used in many dishes. I wondered at the time if perhaps sour cream was called by a different name in England, or was it just not very popular?