While our earlier report focused on the initial four months of the dataset (Saito et al., 2018, Language Learning), this study investigates the relationship between individual differences in motivation (Ideal Self and Ought–to Self), emotions (Enjoyment and Anxiety), and L2 speech learning among 121 Japanese English–as–a–Foreign–Language high school students over 1.5–years. Participants’ L2 speech proficiency consistently improved at each testing point (6 months, 10 months, and 1.5 years), while their motivation and emotions, measured through questionnaires, remained relatively stable. The results of structural equation modeling suggest that the relationship between motivation, emotions, and acquisition may evolve. Within the first 6-10 months, data indicated a correlational relationship, highlighting a mutual influence among motivation, emotions, and acquisition. However, as the study progressed beyond one year, after students had fully adapted to their educational settings, a clearer causal relationship emerged: Enhanced motivation and more positive emotions were linked to increased classroom practice, leading to significant gains in L2 speech proficiency. The predictive roles of Anxiety remained unclear in this longitudinal dataset.

Previous studies show that attention plays an important role in second language (L2) phonetic attainment. This study compares the effect of two high variability phonetic training methods (identification (ID) and categorical AX discrimination (DIS)) on specifically targeted sounds and on implicitly exposed but untargeted sounds. Four groups of Spanish/Catalan bilingual learners of English were trained on either a subset of English vowels (/iː ɪ æ ʌ ɜː/) or word-initial and word-final stops. The study also examined if the potential effect of training generalized to new stimuli and persisted two months after training. Results revealed that trainees significantly outperformed the controls in their identification of targeted sounds, and improvement generalized to new stimuli and was maintained after training, showing the efficacy of both training methodologies. However, while all trainees performed similarly with initial stops, ID trainees outperformed DIS trainees in vowel perception. Interestingly, only DIS trainees showed a significant improvement in the perception of untargeted sounds, indicating that this training method (possibly due to the absence of labels and the exposure to two physically present stimuli in each trial) may be more suited to enhance learners’ perception of both targeted and untargeted sounds.

Building on the extensive work conceptualizing, developing, and validating foreign language aptitude for successful second language acquisition (e.g., Skehan, 2015, in Applied Linguistics), the current project expounded the cognitive abilities relevant and instrumental to adult Japanese classroom learners’ pronunciation attainment of English /ɹ/. The speech production of 50 Japanese participants was elicited, acoustically analyzed, and linked to different aspects of their aptitude profiles (phonemic coding, associative memory, and sequence recognition). Whereas those with higher phonemic coding demonstrated better performance in a relatively easy dimension of English /ɹ/ pronunciation (lower F2 for tongue retraction), those with greater associative memory demonstrated more advanced performance in the relatively difficult dimensions of English /ɹ/ pronunciation (longer transition duration for phonemic length; lower F3 for labial/alveolar/pharyngeal constrictions). The role of incidental learning aptitude (i.e., sequence recognition) remained unclear. The findings here indicate that explicit aptitude related to phonological analysis and memory may play a key role in predicting the incidence of advanced second language segmental proficiency attainment in classroom settings.

The current study examines the role of cognitive and perceptual individual differences (i.e., aptitude) in second language (L2) pronunciation learning, when L2 learners’ varied experience background is controlled for. A total of 48 Chinese learners of English in the UK were assessed for their sensitivity to segmental and suprasegmental aspects of speech on explicit and implicit modes via behavioural (language/music aptitude tests) and neurophysiological (electroencephalography) measures. Subsequently, the participants’ aptitude profiles were compared to the segmental and suprasegmental dimensions of their L2 pronunciation proficiency analyzed through rater judgements and acoustic measurements. According to the results, the participants’ segmental attainment was associated not only with explicit aptitude (phonemic coding), but also with implicit aptitude (enhanced neural encoding of spectral peaks). Whereas the participants’ suprasegmental attainment was linked to explicit aptitude (rhythmic imagery) to some degree, it was primarily influenced by the quality and quantity of their most recent L2 learning experience.

The current project investigated the extent to which several lexical aspects of second language (L2) speech – appropriateness, fluency, variation, sophistication, abstractness, sense relations – interact to influence native speakers’ judgements of comprehensibility (ease of understanding) and accentedness (linguistic nativelikeness). Extemporaneous speech elicited from 40 French speakers of English with varied L2 proficiency levels was first evaluated by 10 native-speaking raters for comprehensibility and accentedness. Subsequently, the dataset was transcribed and analyzed for 12 lexical factors. Various lexical properties of L2 speech were found to be associated with L2 comprehensibility, and especially lexical accuracy (lemma appropriateness) and complexity (polysemy), indicating that these lexical variables are associated with successful L2 communication. In contrast, native speakers’ accent judgements seemed to be linked to surface-level details of lexical content (abstractness) and form (variation, morphological accuracy) rather than to its conceptual and contextual details (e.g., lemma appropriateness, polysemy).