Just how tiny children, who hardly know anything at all, learn their native language with ease is still largely a mystery. But a recent article in Science Advances offers evidence that, when a child hears speech before birth, the complex neurological processes that enable early acquisition of the language are stimulated.

From the open access paper:

Human infants acquire language with amazing ease. This feat may begin early, possibly even before birth (1–5), as hearing is operational by 24 to 28 weeks of gestation (6). The intrauterine environment acts as a low-pass filter, attenuating frequencies above 600 Hz (2, 7). As a result, individual speech sounds are suppressed in the lowpass–filtered prenatal speech signal, but prosody, i.e., the melody and rhythm of speech, is preserved.

Benedetta Mariani et al., Prenatal experience with language shapes the brain. Sci. Adv.9,eadj3524(2023). DOI:10.1126/sciadv.adj3524

Mariani and colleagues exposed 33 newborns whose mothers were native French speakers to Goldilocks and the Three Bears in Spanish, English, and French. They monitored neural activity using electroencephalography (EEG). If they heard French last, their brain oscillations correlated with speech perception and processing showed greater activity. It appeared that they were already primed to start interpreting French from their prenatal experience of hearing their mothers’ — and perhaps others’ — voices.

American Association for the Advancement of Science News provides some background:

Between five and seven months of gestation, a fetus can begin to hear sounds outside of the womb. Just days after birth, infants have shown that they prefer their mother’s voice and native language. Newborns can also recognize rhythms and melodies heard in utero, and prenatal exposure to music may help them to develop musical abilities. But it has been unclear whether the same can be said for language.

Nyla Husain, “Babies’ Brains Are Primed for Their Native Language Before Birth,” AAAS News, 22 November, 2023

As science writer Eric Dolan notes,

The study’s findings shed light on the remarkable capacity of newborns to learn and process language quickly, even before they enter the world. The research also suggests that the human brain may already be optimized for efficient language processing, underpinning the impressive language learning abilities observed in infants.

Eric W. Dolan, “New research suggests babies start learning language before birth,” PsyPost, November 22, 2023

At ScienceAlert, David Nield offers,

Of course, babies are perfectly capable of learning a different language to their birth language – this doesn’t mean that we’re tied to the language our mother speaks. However, it does show evidence that learning starts before birth.

David Nield, “What Your Baby Hears Before They’re Born Really Can Shape Their Brain,” ScienceAlert, 28 November 2023

So the popular (and traditional) idea that we should talk to babies before they are born is borne out by research.

You may also wish to read: Researchers: Conscious experience may occur near time of birth The unborn child’s brain is in a rapid, ongoing, and little understood state of development in any event. We can’t know for sure but increasingly, the evidence favors assuming that some sort of mental development is possible.