Somewhere around the third trimester, most expecting parents get the same piece of advice: talk to your bump. It can feel a little silly, narrating your grocery list to a belly that can't answer back. It turns out there's real substance behind the suggestion.
What's actually happening in there
By around 25 to 27 weeks, a baby's auditory system is developed enough to hear sound from inside the womb, muffled and low-pitched, the way sound travels through water. Your voice, specifically, carries through your body in a way that outside noise doesn't. Babies aren't hearing words yet. They're hearing rhythm, pitch, and the particular pattern of your speech.
Research on newborns has found they show a preference for their mother's voice within days of birth, and some studies suggest a preference for the specific language spoken around them during pregnancy over an unfamiliar one. The working theory isn't that babies are learning vocabulary before birth. It's that they're tuning their ear to the rhythm and sound of language itself, well before they'll ever need to understand a single word.
So what should you actually say?
Nothing scripted, and nothing that requires effort. The content doesn't matter nearly as much as the exposure. Parents who talk, read, or sing during pregnancy tend to keep doing it, out of habit, once the baby arrives, and that's really the point. The benefit isn't a prenatal lesson. It's building the habit of narrating your world out loud, which is exactly what helps language development once your baby is here to actually listen.
A few low-effort ways to do this:
- Narrate ordinary tasks: "Now I'm folding this towel," "Let's see what's for dinner."
- Read out loud from whatever you're already reading, a novel, a recipe, the news.
- Sing whatever you already know the words to. It doesn't need to be a lullaby.
Where this goes after birth
The real payoff starts once your baby can see your face and respond to your voice directly. Between birth and their first birthday, babies move from recognizing voices to babbling to understanding far more than they can say. This is the exact window our My First Words book series is built for: real photographs and simple, consistent words that give you something concrete to narrate together, once "just talking" starts to feel like it needs a little more structure.
If you're not there yet and still in the getting-ready phase, our free guide, The First 90 Days, covers what to actually prepare for before baby arrives, plus a full section on what your newborn is learning in their first year.
This article is general information based on published research, not medical advice. For questions specific to your pregnancy, talk to your OB or midwife.