Does your baby razz constantly?

My daughter, who will be 7 months old on Saturday, razzes practically from the time she wakes up in the morning until she goes to bed at night. She's an extremely happy, content baby...and her razzing is always in conjunction with lots of smiles, squeals, and laughs. She's been razzing on a constant level for about three weeks or so, although she learned the trick at about three months. Needless to say, mealtimes have become quite interesting, and we're doing our best to ignore it and keep a straight face when she's eating (and simultaneously razzing her food back out!). She's been drooling a lot lately, and chewing on her lips, so I am wondering if the razzing is some sort of teething comfort, or simply self-entertainment. We razzed at her lots when she was tiny...she'd smile and laugh, and it was funny and sweet to see her respond to the goofy gesture. Could it be she's learned to imitate us?