D．Chinese Traditional Treasure-Peking Opera

Throughout the world, parents talk differently to babies than they do to adults. With their young kids, parents use baby talks, featuring long pauses and a roller coaster of pitch（音高）changes.

While parents may feel a bit silly using baby talks, they shouldn't in fact. Babies not only prefer listening to them, but they also learn new words more easily from them. By highlighting the structure of speech, such as the differences between the vowels（元音）"a" and "o", baby talks help babies translate sounds into meaningful units of language.

Actually, the timbre（音色）plays a role. The timbre of an instrument clearly affects how we experience music, but its role in language is less obvious. Looking into the timbre of baby talks, researchers made some surprising discoveries. In a new study published in Current Biology, researchers reported for the first time that mothers shifted their overall vocal timbre when speaking to their babies, as if they were changing their voice into a different instrument to address these unique little listeners.

In the Princeton Baby Lab, where researchers study how children learn, they recorded English-speaking mothers while they talked with their 7-to-12-month-old babies and while they spoke to an adult experimenter, and found that adult-directed and baby-directed speech had consistently different timbres.

Most surprising, in a second sample of non-English-speaking mothers, researchers found that this timbre shift was also highly consistent across nine diverse languages. This suggests these timbre shifts may represent a universal form of communication with babies.

Being able to identify baby talks across multiple languages could give us rich information about the amount and type of language children hear at preschool across different cultural environments. This could help researchers and educators predict and improve outcomes such as vocabulary and success at school.

Parents should feel self-conscious about their own baby talks: with them they' re helping their baby learn.

12．What is the advantage of parents' using baby talks?

A．It is good for babies to change pitch.

B．It helps translate sounds into different languages.