The Role of Theory in SLA Empirical Research on the Critical Period Hypothesis

This paper sets out to peruse the role of various theories or more precisely, hypotheses invoked in SLA research by surveying three empirical studies pertaining critical period hypothesis phonetics and phonology. In particular, which will be reviewed next section are titled chronological order as (1) A for learning pronounce foreign languages? (Flege, 1987); (2) Reexamining hypothesis: case study successful adult a naturalistic environment. (Ioup et al., 1994); (3) Ultimate attainment L2 Phonology: The Critical Factors Age, Motivation, Instruction (Moyer, 1999).