hi
my dd is 18 weeks now and she does the same thing from time to time: wakes up in the middle of the night and has a "proper conversation" with herself...
she's also rolling around in her crib...
I don't feed her unless I'm sure she can be hungry [as she's on 4 hrs EASY now no sooner than after 4 hrs from her latest feed].
so I suggest if your dd is just cooing [which can be loud...] and goes back to sleep eventually, don't try to feed her. she's practicing new skills probably. but if she starts to cry 3 or 4 hrs after her feed, she may be hungry. I guess babies tend to get hungrier when they're getting more mobile during the day [or day and night...
]
HTH
Monika