Why does bud think that they speak a different language in Grand rapids?

There's no evidence that Bud thinks people in Grand Rapids speak a different language. Bud is a character from the book "Bud, Not Buddy" by Christopher Paul Curtis. He travels to Grand Rapids, Michigan, hoping to find his father.

It's possible you're thinking of a different character or story. Could you provide more context or details about the character and the story? This will help me understand your question better and provide a more accurate answer.