my baby is 7 month she use to say mum mum when she was 6 month old but now she does not say mum mum why?

A. hi dear By this age, most babies can roll over in both directions — even in their sleep. Some babies can sit on their own, while others need a little support. You might notice your baby beginning to scoot, rock back and forth, or even crawl across the room. Some babies this age can pull themselves to a standing position.