While not all babies develop at the same speed, some babies start cooing at around two months. Babies also may blow bubbles during this time as well.
Babies coo as a means of communicating. When parents speak gently to their babies, they coo, blow bubbles or mimic facial expressions to communicate. At around four months, babies also may begin smiling and waiting for their parents to smile back at them. Parents should also take this time to have conversations with their babies by mimicking the sounds that their babies make. Babies tend to respond and communicate with a female voice.