You may have heard (or read) about your baby’s mental and especially auditory development. If you haven’t asked specifically about the baby’s development in the womb, you may only have heard about hearing milestones after birth. Language — not just the ability to talk, but the ability to recognize speech patterns and try to join in — is one of the developmental milestones that people care the most about, but we don’t tend to see significant signs of it till months after birth.

The thing is, this development begins before birth. Your baby’s inner ear becomes fully developed somewhere around the 20th week — only a little more than halfway through pregnancy! And though it’s true that the parts of the brain involved in hearing are still developing, we know that your baby’s auditory environment affects your baby even before birth.

What does an unborn baby hear? Your heartbeat. The grumbling of your stomach. Coughs or burps or hiccups. And especially your voice.

Your baby also gets the muffled sounds from the outside world, but your baby really hears your voice as it travels through your body. Many parents have thought their newborns recognized mommy’s voice, either being calmed by it or becoming more alert. They were right; it was shown that newborns can recognize and prefer their mother’s voices over other women’s back in the ’80s.

Not only can your baby recognize the sound of your voice from the womb, but your baby can also make out speech rhythms — they’ve even been shown to recognize the difference between familiar and unfamiliar languages, and familiar and unfamiliar words!

We don’t know what the long-term effects of different auditory experiences in the womb might be for baby. There’s no good research on the relationship between being read to in the womb and how quickly a baby learns language. There’s no proof that reading to your unborn baby will help your baby become a reader.

But talking to your baby is a great bonding experience. Your baby can hear you. Reading to your baby — exposing your baby to the calm tones of your voice and the rhythm of your language — may have all sorts of benefits for your baby’s mental development. At the very least, you’re familiarizing your baby with the sound of your voice.

If you want more about the research on auditory learning in the womb, this Science news article is a great read.