Which Statement Best Reflects What Researchers Have Learned About Infant-Directed

Which statement best reflects what researchers have learned about infant-directed speech?

A) Infant-directed speech is harder to learn than adult-directed speech.
B) Infant-directed speech is easier to listen to but does not help infants discriminate among other speech sounds.
C) Infant-directed speech benefits infants if presented in quick, short messages.
D) Babies prefer to listen to infant-directed speech relative to adult-directed speech.
E) Infant-directed speech is something adults use, but siblings and other children would not use this with infants.