Is she, or her family, Muslim French-Caribbean? Many locales in the Caribbean were historically controlled by the French for some time. Many Caribbeans moved to the US, and many would have settled into, broadly, black communities. Many black people in the US converted to Islam.

If she fits this description, it’s perfectly reasonable that she has spent much of her life taking to people with American, French, Caribbean, and Arabic accents. It’s also possible that she consumes media where speakers have those accents. As, elsewhere noted, we tend to mimic accents somewhat, especially with consistent exposure.

It’s perfectly reasonable that, shortly after spending some time around a certain accent, or while discussing a topic predominantly discussed with those of a certain accent, she may slip into one herself.