Baby's first word, maybe (4)
(Other definitions for mama that I've seen before include "Mother" , "Dam" , "Mature woman" , "Mummy" , "Mum" .)
'baby's first word maybe' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for dada that I've seen before include "Man Ray's art movement" , "Post-WWI anarchic movement" , "modern artistic movement" , "artistic trend" , "movement in art and literature" .)