Stages of the semiotic capacities and language acquisition

age	phase	features
- 3 months	prenatal	child gets accustomed to his mother's prosody and paralinguistic intonation
7 months	prelinguistic, babbling	screams to express disagreement
9 months		uses gestures
12 months	holophrastic	executes basic (non-linguistic) communicative acts produces one-word utterances
18 months	two-word phase	produces pre-grammatical two-word utterances
2 years		understands and produces multi-word utterances based on specific items
3 years		understands and produces simple sentences based on structural rules still processed holistically; expands the lexicon
4 years		forms complex syntactic constructions by involving Broca's area
4.5 years		forms constraints against overgeneralization
6 years	primary school	learns reading and writing
10 years		speaks with the articulatory precision and speed of adults