At Birth: up to 2 months
- show a preference for language over other kinds of sound or noise
- capable of differentiating the basic sound categories or
phonemes of all the
world languages
- have the vocal tract of a nonhuman mammal
- communicates with cries, grunts, sighs, clicks, stops and
pops associated with breathing, feeding, and fussing.
- first smiles between 6 to 8 weeks
2 months to 5 months
- coos and laughs are added