“Why is dada usually a child's first word?”

The early developing consonants are usually /m,b,d,p/ and children beginning producing those consonants with vowel combinations when babbling. “Mama” or “dada,” normally get a big reaction from parents so they begin using that combination for attention.

Well there is an abundance of data showing some variety in first words. It depends on the child. Babies 3-6 months old play with their mouths, they'll bring their lips together to say "m" and will repeat double syllables so some kids may actually say mama first. But other kids 6-9 months approximately are forming different consonant sounds with their mouths and lips and their tongue is already exploring their mouth, its literally already in place to produce the "d" and dada can be produced. It depends on the child and there is no one generic answer for that question.

Actually, "mama" is more often the first word spoken, but the debate is whether it is because bilabials are the first sounds (?m?, /b/, and /p/ sounds) or due to the fact that the mother is more often the initial primary caregiver.

Mama is actually easier for infants to say than dada. ... However, "mama" only requires the lips to open and close. Infants have traditionally said "dada" first because while in the home with their mothers all day they hear talk about their father.

"Dada" is a very common first word due to its placement in the mouth with the tongue and for its repetitive simplicity of CVCV (consonant vowel consonant vowel) structure.

Ali Matisse, MS CCC-SLP