Talking in his sleep?

REM disorder with Parasomnia, the acting out of vivid dreams.
This is what I remember reading about, in that the normal inhibition of hitting out, talking, even getting out of bed, is not working. It MAY be associated with Lewy's Dementia, and is known to occur with Parkinson's Disease. But it may be present in some people throughout much of adult life.
Can find out tons about it online.

It's not hallucinations or weird. Have you ever had a dream that seemed real when you awoke? My wife used to talk in her sleep and some of it was quite hillarious. If you're concerned talk to his dr. especially if he tends to act out his dreams.

It seems to be new but I've never lived with him/around him to this extent. I know he's not deeply sleeping due to a sleep study he had recently (hoping to get him to use a Cpap). Hopefully that's it, and it's no the beginning of hallucinations or sleep wandering.

Is it a new thing? That is to say, in the past have you noticed your father to talk in his sleep? Most people have something that inhibits them, while sleeping, from acting out, speaking out, and for some actually leaving the bed and "sleep walking". But some few do not. My bro would speak out in his sleep all his life, and it was usually when he was having a dream that was more disturbed. It may have increased later in life as his early Lewy's Dementia started, but he did always have it, and his various partners in life often would laugh with him, with me, about his unintelligible babble, often accompanied by a couple of good kicks in bed. There are levels of sleep at which we tend to dream more than other levels. Your father may be sleeping less deeply than he used to. I would look some of this up online, and consider asking his doc next appointment.

Pretty normal if you go by my mother. She has entire phone conversations by pulling the edge of her sweater over her nose and using her voice and another one for who's on the other end.

Later she'll ask me, "Did I talk to so-and-so, or did I dream it?"

Check his meds.