When you were just a tiny baby, you probably cried a lot – just like every other baby. A few months later, you started to make sounds called babbling. By the time you were six or eight months old, your babbling might have started to sound a bit like words in the language you heard most often at home. At the age of one or two, you could probably use a few words. By about age five, you could speak well and understand what people said to you.

Your language learning is still continuing now and will likely go on for many more years. How did this lifelong process of language learning start? Until recently, researchers believed that children began learning to speak and understand a few months after birth. Now, however, some researchers believe that children might begin to learn even earlier, maybe even before they are born.

How do researchers know how much babies understand when they are still unable to speak? One way is to watch how they react when they hear the sounds of the language their parents use. An experiment with babies who were only a few hours old showed that the babies reacted differently to sounds from their parents’ language than to sounds from a foreign language. Languages all over the world have many similar sounds, but often they are pronounced slightly differently. That is especially true with vowels like a and e. When English speakers use these sounds, they normally add a y sound at the end and thus actually use two vowels instead of one. Other languages, however, are different. Making the vowel sounds from different languages allowed researchers to see that babies seemed to react to the sounds of their own languages.

Another way that researchers could tell how much language babies had learned before birth was to listen to them crying. To most people except the parents, one baby’s crying can sound very much like another’s. However, researchers have noticed that babies seem to cry differently depending on the tones and melodies of the language they hear. If people tend to raise their voices at the ends of sentences or talk in a musical way, babies will also use that sound pattern when they cry. French babies, for example, tend to cry with a rising sound at the end like the language they hear around them. German babies use a falling tone at the end like their parents do when they speak. Although some researchers think the babies might just be imitating their mothers, others think that children might already be learning their language.

As they grow up, children slowly learn to speak and later to read and write. Researchers know a lot about the different stages of learning, such as when children usually begin to use single words and when they start to use sentences. This new research, however, could change the way people think about babies and language learning. Who knows how that knowledge will help children and parents in the future?