I teach middle school English and we read a novel called "The Cay." It is about a blind boy and an old man shipwrecked in the Caribbean. In an interview with the author, Theodore Taylor, students ask him what is the correct pronunciation of his novel. He says "kay," but says many pronounce it "key" as well. Both key and cay mean the same, small islands. However, he mentions that many of the local natives refer to the word as cai (pronounced "ki"- long i sound like in "kite.") So there is a third pronunciation. Whatever the name, it is paradise.