This study examined the componential structure of second-language (L2) speaking proficiency. Participants—181 L2 and 54 native speakers of Dutch—performed eight speaking tasks and six tasks tapping nine linguistic skills. Performance in the speaking tasks was rated on functional adequacy by a panel of judges and formed the dependent variable in subsequent analyses (structural equation modeling). The following independent variables were assessed separately: linguistic knowledge in two tests (vocabulary and grammar); linguistic processing skills (four reaction time measures obtained in three tasks: picture naming, delayed picture naming, and sentence building); and pronunciation skills (speech sounds, word stress, and intonation). All linguistic skills, with the exception of two articulation measures in the delayed picture naming task, were significantly and substantially related to functional adequacy of speaking, explaining 76% of the variance. This provides substantial evidence for a componential view of L2 speaking proficiency that consists of language-knowledge and language-processing components. The componential structure of speaking proficiency was almost identical for the 40% of participants at the lower and the 40% of participants at the higher end of the functional adequacy distribution (n = 73 each), which does not support Higgs and Clifford’s (1982) relative contribution model, predicting that, although L2 learners become more proficient over time, the relative weight of component skills may change.

This study assessed knowledge of numerically quantified English sentences in two learner populations—second language (L2) learners and deaf learners—whose acquisition of English occurs under conditions of restricted access to the target language input. Under the experimental test conditions, interlanguage parallels were predicted to arise from acquisitional pressures imposed by derivational economy on universal grammar (UG)–guided semantic interpretation. The results of a task in which participants matched sentences to multiple discourse depictions confirmed the predicted parallels. However, in matching underinformative sentences to depicted contexts, the L2 and deaf learner groups overactivated discourse-pragmatic knowledge. The restriction of indefinite noun phrases to singleton indefinites and the cancellation of scalar implicatures rendered sentences more informative in underinformative contexts, producing incorrect—although principled—interpretations. These results inform English acquisition at the interface of semantics and discourse pragmatics and provide further support that economy pressures yield L2 learner and deaf learner interlanguage parallels as observed, for instance, in learners’ interpretative knowledge of universally quantified English sentences.

Using the eye-movement monitoring technique in two reading comprehension experiments, this study investigated the timing of constraints on wh-dependencies (so-called island constraints) in first- and second-language (L1 and L2) sentence processing. The results show that both L1 and L2 speakers of English are sensitive to extraction islands during processing, suggesting that memory storage limitations affect L1 and L2 comprehenders in essentially the same way. Furthermore, these results show that the timing of island effects in L1 compared to L2 sentence comprehension is affected differently by the type of cue (semantic fit versus filled gaps) signaling whether dependency formation is possible at a potential gap site. Even though L1 English speakers showed immediate sensitivity to filled gaps but not to lack of semantic fit, proficient German-speaking learners of English as a L2 showed the opposite sensitivity pattern. This indicates that initial wh-dependency formation in L2 processing is based on semantic feature matching rather than being structurally mediated as in L1 comprehension.

With Russian as the target language, a proof of concept study was undertaken to determine whether it is possible to identify linguistic features, control over which is implicated in progress on the Interagency Linguistic Roundtable (ILR) proficiency scale, thereby better to inform the instructional process. Following its development in an instrumentation study, a revised version of a computer-delivered battery of 33 perception and production tasks was administered to 68 participants—57 learners between levels 2 and 3 (21 at ILR 2, 18 at 2+, and 18 at 3) on the ILR scale, and 11 native speaker controls—whose proficiency was tested via an ILR oral proficiency telephone interview. The tasks sampled subjects’ control of Russian phonology, morphology, syntax, lexis, and collocations. Relationships between control of the linguistic features and the ILR levels of interest were assessed statistically. All 33 tasks, 18 of which assessed learners’ abilities in perception and 15 of which assessed their abilities in production, were found to differentiate ILR proficiency levels 2 and 3, and a subset was found to also distinguish levels 2 and 2+, and 2+ and 3. On the basis of the results, a checklist of linguistic features pegged to proficiency levels was produced that can be useful for syllabus designers, teachers, and learners themselves as well as providing the basis for future diagnostic tests.

Recent literature has sought to understand the presence of epenthetic vowels after the productions of postvocalic word-final consonants by second language (L2) learners whose first languages (L1s) restrict the presence of obstruents in coda position. Previous models include those in which epenthesis is seen as a strategy to mitigate the effects of coda licensing restrictions in the L1; others see epenthesis as a result of misperception of consonant releases in the L2 as indicating the presence of an additional syllable nucleus. The current study examines segmental identification and syllable counting in inexperienced Korean learners of English as a foreign language. Across stimuli, two effects were found. Increased perceptual epenthesis correlated with increased identification of a segment as voiceless, indicating a joint perception of voicelessness and an epenthetic vowel. Also, rate of epenthesis increased with accuracy of detecting sibilants and coronal segments, sounds characterized by salient consonant noise. Taken together, these results indicate a perceptual mechanism that evaluates segmental content and prosodic structure from an integrated percept. Analyses across individual listeners do not support a model in which perceptual epenthesis is a strategy to increase segmental accuracy; rather, they support models in which both syllable counting and segmental identification are skills that are reflections of increased proficiency in the L2. These results are discussed with respect to models of L2 phonology that rely on the robust encoding of lexical items.