Katie and I don't use baby talk around Rosie. We talk to her normally, mainly because that's better for children developmentally. Another reason we don't use baby talk is because it's annoying. I occasionally will use a cutesy tone of voice when talking to Rosie, because she's sooo cute, but other than that, I abide by the "no baby talk" rule.
Rosie makes some noises which sound like real words. Mainly, it's the standard "wah-wah" cry. If her tongue is on the top of her mouth when she does that, it comes out like "mwa-mwa", which sounds like "mom". If her tongue is on the bottom of her mouth, it comes out like "nuaa-nuaa", which sounds like "no".
Obviously, this doesn't happen all the time. But if she just happens to emphasize the correct part of the "wah" sound (the one sounding like "oa"), with a slight "m" or "n" in front, it sounds like "no" or "mom". It's kind of fun to pretend she is saying those words on purpose, and not by accident.