My dd was doing that and it really got "old" fast, so we picked out accents for her to listen to and we all tried to talk like that too. English, Irish, Long Island, Bostonian, etc. She is almost 8yo now and can mimic most of them proficiently! DD is now working on cartoon and environmental noises. This too can get annoying but most often it is hilarious!!! (and the baby talk has been a thing of the past!)