It depends on what amount of time we're talking about. Of course, I have those first few moments when I wake up and am totally disoriented because I haven't yet woken up mentally. When I was younger and my mother used to come to my bedroom to wake me up for school, she always had to turn the light on to get me to wake up. Before she started doing that, she'd just tell me to get up, and I'd apparently talk to her without actually waking up, and she thought I was going back to sleep when I'd never really woken up to begin with. Additionally, if I wake up to the phone ringing, I usually answer it with urgency (which is weird because I don't do that at others times), but I won't be able to understand anything that's being said. I can register that someone is talking to me and say something like, "I don't understand you," but (obviously) I have no idea what they're actually saying. It's like listening to someone speak a foreign language you aren't familiar with.
But that's only for a couple of minutes at the most. I wake up very quickly, and I'm totally a morning person.