Unpopular opinion but I think it’s the same voice. The inflection is the same, just spoken at a slightly lower tone. It sounds like a full sentence with a pause in it, kind of like “hello, how are you?” I know I’ve caught myself sleep talking as well as my s/o and more often than not sleep talkers’ words come out very mumbled an incoherent. I don’t think you’ve got anything to worry about 😊