What term describes the modified speech adults use when talking to infants?

The term that describes the modified speech adults use when talking to infants is "Parentese." This type of speech often features a higher pitch, exaggerated intonation, slower tempo, and clear pronunciation, all of which are designed to capture an infant's attention and aid in language acquisition. Parentese facilitates effective communication and helps infants learn the sounds and rhythms of their native language.

While "Infant-directed speech" is another common term used to describe this phenomenon and overlaps significantly with parentese, it is slightly broader and encompasses various modifications in speech. The distinction lies in the focus; parentese specifically emphasizes the characteristics of speech adults use with infants, including its playful and nurturing quality. "Child-centered conversation" and "Child-talk" are not widely recognized terms in linguistic studies, and they do not specifically reflect the unique speech alterations characteristic of interactions between adults and infants.