The end of infancy is marked by the acquisition of language.
Language is a complex cultural artifact.
Its acquisition is complex, and takes several years.
Piaget emphasized that language is a system of symbols, to represent the world.
Early social interaction, combined with cognitive developments (esp. capacity for representation) provide the basis for language.
Language acquisition builds on the ability to use symbols, and adult scaffolding.
Children must acquire the 4 subsystems of language: phonemes, lexicon, syntax, & pragmatics.