Some babies spend most of their waking time with only one person; others hear speech from many different speakers. Even if these two babies hear the very same words, their experiences are not the same. Researchers from the EU-funded VIOLA (Variability's Influence on Language Acquisition) project asked themselves, is language-learning affected by the number of people speaking around the child? Is it better if one person is speaking to the child all the time, or if the baby is exposed to many voices? They found that although babies should find it more difficult to pick up language when many people are talking (even if they are speaking normally, in conversation), babies between four months and one year seem to learn sounds and words anyway. It appears that at an early age babies can ‘filter out’ or adapt to differences between speakers’ voices. The VIOLA researchers also found evidence that both word-learning and sound-decoding skills emerge in parallel. No one type of childcare is better than another The results suggest that neither exposing children to large groups of people nor speaking to them one-on-one improves language uptake. This has implications for national-level policymakers, who are often responsible for the childcare systems within their own countries. “Based on the results obtained, it is possible to tentatively state that all types of caregiving arrangements are similarly beneficial, and that there is no single type that is superior to others,” said Dr Christina Bergmann, who led the project at the Ecole Normale Superieure in France. In the ‘babylab’ The researchers carried out tests on actual babies while simultaneously running models and simulations. Since a lot is already known about how we perceive speech from ear to brain, the scientists used existing models to answer a new question, namely how easy it is to distinguish sounds in the presence of many voices. Infants were shown two pictures, for example of a dog and a bottle, and the scientist named one of the two, checking which picture the baby looked at. It is an automatic reaction to look at the correct picture if you know the word, and the researchers assessed if the babies did this. In another test, the babies sat in a darkened room, listened to made-up words and watched an image on a screen, and the scientists measured how long they liked to listen. It was a challenge for researchers to correctly interpret the babies’ reactions, however. “It’s really complicated because we can’t just ask babies [what they hear] like we do with adults. They sit in a dark room and there’s a nice picture on a screen and at the same time we play sounds and then when they get bored they start looking around the room.” says Dr Bergmann. “It’s very indirect.” Moving forwards, the next steps will be to examine how infants learn words in daily life. The focus will now be on other key aspects of infants’ environment, including how caregivers talk to their child and what a typical day for a child looks like. All these factors can help shed light on how infants acquire language and what they need to experience to learn words and ultimately their mother tongue.
VIOLA, language development, language acquisition, babies, infants, child development, speech, language, childcare