Result of work of psychologists Pavlov, Watson and B.F. Skinner as well as linguists Saussure, Bloomfield, Lado and Fries. Behaviorists suggests that children were born with a clean slate, which they add to via immitation of parents and caregivers.
Structuralists viewed language as primarily oral and so emphasized phonology and morphology. They believed that language is best learned inductively and indirectly and promoted practice over explanation. Conditioning through stimulus and response can promote learning.