Carey’s speaking voice is relatively low, which explains why she’s able to reach deeper notes and sing in husky tones as well as a high, clear soprano. But the whistle register has been something she has worked on for a lifetime. She explained in 1998 that the range is the result of nodules on her vocal cords - normally something that considerably hampers a singer’s career, but which Carey uses to “have the high register and the belting register and still be husky.”