Why do people in cabash speak french?

There is no place called "Cabash". It's possible there's a misspelling or a less common name.

Could you please clarify:

* Is there a specific place you're thinking of? Can you provide more context or details about where this place might be located?

* Are you referring to a specific group of people? If so, what are their characteristics or background?

With more information, I can help you understand why people might speak French in that place.