Infants' repetition of certain syllables at the age of about 6 or 7 months is called:

A) cooing.
B) holophrasing.
C) gurgling.
D) babbling.

Babbling

An early stage of language development in infants, characterized by repetitive sounds and syllables without specific meaning, as a precursor to speech.

Syllables

Units of pronunciation having one vowel sound, with or without surrounding consonants, forming the whole or a part of a word.

Holophrasing

The use of a single word to express a complex idea, often observed in the early language development stages of children.