Behaviourism

Skinner

Instinctive & Innate ability

Chomsky

LAD works in a Critical Period

Lennenburg

WUG test

Jean Berko

Interactionism:
Child Directed Speech

Bruner

Construction Theory (usage based)

Tomasello

Cognitive/intellectual development & language development

Piaget

Social Interactionist

Vygotsky
(variant on Bruner)