baby talk vs motherese

baby talk and motherese both are nouns.

Word	Noun	Adjective	Verb	Adverb
baby talk	Yes	No	No	No
motherese	Yes	No	No	No

As nouns, baby talk and motherese are synonyms defined as:

baby talk and motherese: an adult's imitation of the speech of a young child

Other synonyms of baby talk include babytalk.

baby talk (noun)	motherese (noun)
the developing speech of a young child	an adult's imitation of the speech of a young child
an adult's imitation of the speech of a young child