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S#*@! Your Baby Can Hear You

Uh-oh. Better back off on the f-bombs a few months before the baby is born.

A new study out of Finland has found that newborns emerge from the womb already knowing words they frequently heard while innocently gestating and eavesdropping on your private, adult conversations. The good news is that typical newborns aren't born talking, so your potty-mouth secret is still safe until the more verbal toddler years.

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How do scientists know that babies pick up a little vocab in utero? Researchers have long known that babies emerge already familiar with the sounds, stress patterns and intonation of the language or languages that surrounded their mothers during pregnancy. Building on those findings, a group in Finland set up a study to see if fetal brains were also wiring up and storing specific words.

Researchers don't know how long these word memories last—or how far back they are formed.

Around half of the 33 Finnish women in their final trimester blasted a recording that mainly repeated the fake Finnish-like word "tatata" five to seven times every week. Once in a while, the recording sounded a slightly altered version of the fake word, one that kind of broke the rules of intonation for Finnish. Five days after the babies were born, researchers hooked up electrodes to their little heads and replayed the recording. When the ones exposed to the "tatata" soundtrack in utero heard the altered version, their brains shot off synapses indicating they heard something new—that they recognized a distinction between the regular "tatata" and the wacky one. The brains of babies whose moms hadn't played the endless loop of "tatata" in the final weeks of gestation didn't show they noticed a difference.

Researchers don't know how long these word memories last—or how far back they are formed. The babies in the study heard the final recording five days before birth, according to a science news report on the findings. (How five days before birth was calculated, unless all of the women had been scheduled for birth, is unclear.) In any case, understanding when this kind of word-level language acquisition starts could eventually give insight for when and how to help children who are likely at risk for certain language disorders. In other words, more research might reveal strategies for mega-early intervention.

RELATED: My Toddler Isn't Talking, Now What?

The study, coauthored by Eino Partanen of the University of Helsinki, appears in the Aug. 26 issue of the Proceedings of the National Academy of Sciences.

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