| This study assessed how learners' first language (L1) and their learning experience interact in acquiring second language (L2) phonology if exposure to the target language (TL) starts post-pubertally. According to the Critical Period Hypothesis, it is impossible to acquire native fluency in a language after puberty. The Speech Learning Model posits that, unlike the Contrastive Analysis notion ("the more different L1 and L2 are, the more difficult"), a partial similarity of L2 to L1 can be detrimental. Lengthy exposure to L2 enables learners to establish categories for "new" sounds, whereas equivalent classification, or replacement of L2 features with neighboring L1 sounds, blocks the learners' access to "similar but not identical" sounds. It was hypothesized that "similar" sounds would be difficult, regardless of learners' developmental stages, but that the experienced subjects, having established categories, would produce and perceive "new" sounds authentically. Eighty-two nonnative speakers whose L1 was English, Chinese, or Korean, and eight native speakers of Japanese, participated in the experiments. In Experiment 1, global foreign accent was evaluated by a sentence reading task. In Experiments 2 and 3, subjects demonstrated their ability to produce and perceive "new" and "similar but not identical" sounds. There was not a single non-native subject whose global foreign accent was judged as native-like; however, several subjects produced and perceived isolated words within the native range. For all of the experiments, the L1 effect was found to exist. These findings challenge the view that the critical period for L2 is an all-or-nothing phenomenon biologically constrained in any language learning situation. Adult learners' degree of performance in producing and perceiving L2 sounds is highly affected by the relative distance between L1 and L2. |
