There's Illinois, which has a silent "S" as a French word would be expected to.

But Cairo, IL is pronounced like (KAIR-oh) and not like the Egyptian city.

For Marseilles, IL and Des Plaines, IL you would pronounce every "S". But for Des Moines, IA you would not.

While I'm stuck on Illinois and French, there's also Joliet with the pronounced "T" and Champaign pronounced like the French drink.

Baton Rouge, LA is kind of halfway between French and English.

We say Paris, TX like we say Paris, France... but that's not how the Parisians do.

I guess I'm just looking for any little insight into some places named after either people or other places from a particular language. I know "why" questions are often nearly impossible to answer, but I also know we sometimes intentionally change names to things like "freedom fries" and "victory cabbage".