Individual differences in second language speech learning in classroom settings: roles of awareness in the longitudinal development of Japanese learners’ English /ɹ/ pronunciation

The current study longitudinally examined a crucial individual difference variable—i.e., awareness (operationalized as explicit attention and articulatory knowledge)—in adult second language (L2) speech learning in the context of 40 Japanese learners’ English /ɹ/ pronunciation development in an EFL classroom. The participants’ speech, elicited from word reading, sentence reading and timed picture description tasks at the beginning and end of one academic semester, were analyzed in terms of three acoustic dimensions of English /ɹ/—third formant (F3), second formant (F2) and duration. Whereas the participants showed gains in the relatively easy aspect of the English /ɹ/ acquisition (F2 reduction) as a function of increased L2 input, their explicit awareness of accurate English /ɹ/ pronunciation played a significant role in the acquisition of the relatively difficult dimension (lengthening phonemic duration). The awareness-acquisition link was not found, however, for the most difficult dimension (F3 reduction) at least within the timeframe of the project