Ars Technica writes Infants remember speech heard in the womb.
"Partanen wanted to explore this on a more detailed level. ‘Can babies learn from the music, speech, stories that they hear from the womb?’ he said. ‘We were interested in looking at this from a neurophysiological angle.’
In order to find out, Partanen and his colleagues used basic sounds. The fetuses in their studies were not played opera or told fairy tales: instead, participating families played multiple recordings of a sound several times a week during pregnancy. This sound was the pseudoword ‘tatata.’ Occasionally this sound was varied with a subtle pitch increment in the middle syllable.
Very soon after birth, researchers compared responses to these sounds when they were played to infants who had been exposed to it while in the womb, as well as those who had not. When recording the electrical activity of the brains of the infants using EEG, they found that the infants who had been exposed to the sounds previously reacted much more strongly to them. Furthermore, these infants were capable of discriminating the small pitch differences between the two versions."