BACKGROUND: Studies have shown that infants learn language faster when what they see is synchronized to the sound that they hear. The visual clues also help infants cope with learning a language in noisy environments.
HOW WE LEARN LANGUAGE: Babies start to babble in strings of words at around six or seven months, but even before that, infants are busy sorting out the sounds and shapes of words and sentences. Unlike the printed word, speech doesn't use commas, spaces or periods to separate words and concepts. So if there is background noise, it's harder for the infant to known when one word ends and another begins.
THE RESEARCH: Four studies involving 116 infants were conducted at Johns Hopkins University in 2002 analyzed how noise nearby affects 7-month-old infants during this early stage of language development. The babies were shown different videos of a woman talking while emphasizing a specific word, such as "cup." In one version, the audio matched what the woman was saying; in another, it didn't; in a third, the audio was matched with a still frame of the speaker.
THE FINDINGS: The researchers found that even moderate background noise can affect how infants learn language, reaffirming how important it is for a child to see the face of a person while hearing him or her speak. Infants who watched the first version of the video, where they could see the woman's face while she spoke, focused on the emphasized word an average of two seconds longer than on the surrounding words. That's a long time in an infant's limited attention span. Background noise -- such as other children playing or watching TV -- poses the same problem for children that an older adult with hearing loss might encounter at a crowded cocktail party.
PARENT PRIMER: So-called "parentese" -- the undulating baby talk most parents employ when speaking to infants -- is actually one of the best ways to help your baby learn language. It highlights the boundaries between words, phrases and clauses, which helps children learn the structure of the language.