When Diana talks to her baby, she uses simple words and short sentences, a high-pitched voice, and exaggerated intonations and facial expressions. Diana is using a form of speech that is formally called:

Answer: Baby Talk

Explanation: baby talk is a speech associated with an adult taking to a child. It is also called care-giver register, care taker speech, infant directed speech.

Baby talk is characterized by a sing song pattern of intonation, higher and wider pitch, short and simple words and slower utterances.

Its visual aspect has to do with the movement of the lips and wider opening of the mouth.

baby talk aids the interaction and bonding with caregivers and it contributes to the mental development of the child.