Confused.

So I currently have a "daddy" & whenever we're talking in person or on the phone he's always talking baby talk to me. I mean yes I talk like a baby at times but when I'm not even in my little space he still talks like a baby. I ask him if he's the little now all the time & his response is "no I'm not" then he starts right back up talking all babyish. This seems really weird to me...is it normal?