I know she speaks in such a way that Peter can understand her, I just always assumed the tinkering of bells WAS the language. But there aren't many of us earthly humans who speak "Bell", LOL.
However, the idea that maybe she really DOES speak in a language we can understand, yet it's so small that all our human ears can pick up is a bell noise is an interesting perspective that I have not considered before. If Disney gave us that as the official explanation, I suppose I could go along with it.