Among common milestones for this age group:
- Babies coo, making gurgling sounds.
- They turn their heads toward sounds.
From cdc.gov/milestones
Your baby listens to your voice. He coos and gurgles and tries to make the same sounds you make. You can help your baby learn how nice voices can be when you do any of these things:
- Sing to your baby. You can do this even before he is born! Your baby will hear you.
- Talk to your baby. Talk to others when she is near. She won't understand the words, but she will like your voice and your smile. She will enjoy hearing and seeing other people too.
- Plan for quiet time. Babies need time to babble and play quietly without TV or radio or other noises.
From zerotothree.org