Testing the three-stage model of second language skill acquisition

Skill acquisition theory conceptualizes second language (L2) learning in three stages (declarative, procedural, and automatic), yet competing theoretical models with fewer stages also exist, and the number of stages has never actually been tested. We tested the validity of the three-stage model by investigating the number and nature of learning stages in L2 skill acquisition. Seventy-three participants deliberately learned grammar and vocabulary of a miniature language through explicit-deductive instruction. They systematically practiced comprehending the language until their accuracy and speed of performance did not improve anymore. Participants received a battery of tests assessing individual differences in their declarative and procedural learning abilities. We first applied hidden Markov modeling to participants’ reaction time data (obtained from the language practice) to compare rival hypotheses on the number of stages in L2 skill acquisition. We then examined which cognitive variables predicted participants’ performances (accuracy and speed) in each stage. Our results indicated that participants indeed acquired L2 skills in three stages and that their performance correlated initially with declarative learning ability, but there was a tendency for procedural learning ability to take over in the later stages. Our findings provide the first formal evidence for the influential three-stage model of L2 skill acquisition.