"We showed that the foetus during the last ten weeks of the pregnancy not only listens to but remembers and learns languages," Patricia Kuhl at the Washington University Institute for Learning and Brain Sciences told the BBC.
It was already known that babies during their last weeks in the womb could recognize their mother's voice and vocal melody. After studying newborns, however, a Swedish-American team of scientists proved that the babies had learned a lot more than that.
The scientists studied forty infants who were just 30 hours old. The baby boys and girls were then made to listen to vocal sounds in Swedish and English.
The American babies would start sucking their pacifiers more intently when they heard Swedish vowels, which researchers interpreted as a sign of curiosity upon hearing a foreign tongue. The Swedish babies reacted similarly when they heard English sounds.
The researchers concluded that the babies reacted differently to their native tongue and a foreign language, and could, in effect, hear the difference.
The science team said their results proved that language acquisition started in the womb during the last weeks of the pregnancy, when the unborn baby's hearing was fully developed.
Kuhl stated that this discovery could lead to something big.
"The brain goes online like a curious and capable learning mechanism," researcher Patricia Kuhl told the BBC.
"If you release that curiosity anything can happen."
The scientists warned parents, however, against intentionally forcing language learning on their unborn babies, as it could disturb their natural ability to learn through hearing as well as their sleeping cycles.