This article proposes a conceptual and measurement framework for postpubertal, L2 speech learning aptitude that is centered around domain-general auditory processing (i.e., representing spectral and temporal characteristics of sounds). To this end, we examine the construct and reliability of a battery of auditory processing tests by presenting the results of an empirical study wherein 100 participants took the tests twice. The findings showed (a) that the tasks tapped into multiple dimensions of auditory processing ability (e.g., perceptual acuity, audio-motor integration); and (b) that test-retest reliability ranged from “fair” to “excellent” (ICC (2,2) = .4–.8). Last, we introduce an offline version of the tests (deposited at L2 Speech Tools for Researchers & Teachers; http://sla-speech-tools.com/), provide a brief user manual, and invite researchers to use these tests to examine the role of auditory processing in various aspects of L2 speech learning (naturalistic vs. classroom, perception- vs. production-based practice).

Meta-analytic reviews collect available empirical studies on a specified domain and calculate the average effect of a factor. Educators as well as researchers exploring a new domain of inquiry may rely on the conclusions from meta-analytic reviews rather than reading multiple primary studies. This article calls for caution in this regard because the outcome of a meta-analysis is determined by how effect sizes are calculated, how factors are defined, and how studies are selected for inclusion. Three recently published meta-analyses are reexamined to illustrate these issues. The first illustrates the risk of conflating effect sizes from studies with different design features; the second illustrates problems with delineating the variable of interest, with implications for cause-effect relations; and the third illustrates the challenge of determining the eligibility of candidate studies. Replication attempts yield outcomes that differ from the three original meta-analyses, suggesting also that conclusions drawn from meta-analyses need to be interpreted cautiously.

The current study set out to examine to what degree age of acquisition (AOA), defined as a learner’s first intensive exposure to a second language (L2) environment, mediates the final state of postpubertal, spoken vocabulary attainment. In Study 1, spontaneous speech samples were elicited from experienced Japanese users of English (n = 41) using storytelling and interview tasks. The samples were analyzed using a range of corpus- and rater-based lexical measures and compared to the speech of inexperienced Japanese speakers (n = 40) and native speakers of English (n = 10). The results showed that most experienced L2 learners tended to demonstrate nativelike proficiency for relatively easy lexical dimensions of speech (i.e., richness), but that AOA appeared to play a key role in predicting the ultimate attainment of relatively difficult lexical dimensions (i.e., appropriateness). In Study 2, the findings were successfully replicated with experienced L1 Polish users of English (n = 50).

Recent studies on the learning of L2 prosody have suggested that pitch gestures can enhance the learning of the L2 lexical tones. Yet it remains unclear whether the use of these gestures can aid the learning of L2 intonation, especially by tonal-language speakers. Sixty-four Mandarin speakers with basic-level Spanish were asked to learn three Spanish intonation patterns, all involving a low tone on the nuclear accent. In a pre-post test experimental design, half of the participants received intonation training without the use of pitch gestures (the control group) while the other half received the same training but with pitch gestures representing nuclear intonation contours (the experimental group). Musical (melody, pitch) abilities were also measured. The results revealed that (a) the experimental group significantly improved intonational production outcomes, and (b) even though participants with stronger musical abilities performed better, those with weaker musical abilities benefited more from observing pitch gestures.

The current study examined the extent to which cognitive fluency (CF) contributes to utterance fluency (UF) at the level of constructs. A total of 128 Japanese-speaking learners of English completed four speaking tasks—argumentative task, picture narrative task, reading-to-speaking task, and reading-while-listening-to-speaking task—and a battery of linguistic knowledge tests, capturing vocabulary size, lexical retrieval speed, sentence construction skills, grammaticality judgments, and articulatory speed. Their speaking performance was analyzed in terms of speed, breakdown, and repair fluency (i.e., UF), and scores on linguistic knowledge tests were used to assess students’ L2 linguistic resources and processing skills (i.e., CF). Structural equation modeling revealed a complex interplay between the multidimensionality of CF and UF and speaking task types. L2 processing speed consistently contributed to all aspects of UF across speaking tasks, whereas the role of linguistic resources in speed and repair fluency varied, depending on task characteristics.

Following calls for more modality-sensitive perspectives of SLA, this study investigated the extent to which (a) producing the second language (L2) in the oral modality impacts learner-generated noticing and L2 development of grammatical structures embedded in subsequent auditory input, and whether (b) engaging in L2 production and input processing in the written modality differentially contributes to learner noticing and L2 outcomes compared to the oral modality. Participants were beginner-level L2 Spanish learners assigned to one of three pedagogic task conditions (No-output, Speaking, Writing). Two target structures differing in their relative intrinsic salience were considered in the study. Learners’ noticing behaviors were gauged using stimulated recall protocols, and L2 grammar development was measured using pre-, post-, and delayed posttests of production and written and aural acceptability judgment. Results revealed that engaging in oral output promoted greater noticing and deeper analysis of auditory input as well as more robust L2 grammar development compared to no output. However, sustained linguistic gains on the lower-salience target structure were only observed among participants who engaged in output and input processing in the written modality.

In this study, we propose a hypothesis that domain-general auditory processing, a perceptual anchor of L1 acquisition, can serve as the foundation of successful post-pubertal L2 learning. This hypothesis was tested with 139 post-pubertal L2 immersion learners by linking individual differences in auditory discrimination across multiple acoustic dimensions to the segmental, prosodic, lexical, and morphosyntactic dimensions of L2 proficiency. Overall, auditory processing was a primary determinant of a range of participants’ proficiency scores, even after biographical factors (experience, age) were controlled for. The link between audition and proficiency was especially clear for L2 learners who had passed beyond the initial phase of immersion (length of residence > 1 year). The findings suggest that greater auditory processing skill benefits post-pubertal L2 learners immersed in naturalistic settings for a sufficient period of time by allowing them to better utilize received input, which results in greater language gains and leads to more advanced L2 proficiency in the long run (similar to L1 acquisition).

The current study investigates the effects of more explicit versus more implicit corrective feedback on beginner Mandarin learners’ perception and production of Mandarin tones. The effects of oral corrective feedback have been extensively investigated for various domains of second language acquisition (see Mackey & Goo, 2007). For phonological errors, implicit feedback has shown to be particularly salient to learners (Mackey, Gass, & McDonough, 2000) and therefore potentially more effective for tone learning. However, for lower proficiency beginners, explicit corrective feedback has been shown to be more effective (Li, 2009, 2014). Using a mixed methods design, the current study investigated the acquisition of Mandarin tones in beginner, adult learners (n = 41) enrolled in a 14-week, one-on-one, synchronous computer-mediated communication course. Learners were divided into two experimental groups: a more implicit feedback group and a more explicit feedback group. Pretests and posttests assessed changes in tone perception and production. Upon completion of the course, learners in the more implicit feedback group had greater improvement in tone production compared to the more explicit feedback group (d = .75). Both learners and the instructor indicated a preference toward recasts for tone feedback. No statistically significant differences were found for tone perception.

This study examines the role of language proficiency and other individual factors (attitudes, input) in the acquisition of language-specific [ð] and dialect-specific [∅] allophones of Spanish intervocalic /d/ in the /ado/ context by L2 and heritage Spanish speakers during a short-term study abroad in Sevilla, Spain. Twenty L2-intermediate, 10 L2-advanced, and 10 Heritage-advanced Spanish speakers completed a reading task at the beginning and the end of the program. Based on an acoustic analysis, a mixed-effects linear regression model found that only L2-advanced and Heritage-advanced groups demonstrated more approximant-like [ð] over time. However, proficiency level interacted with attitudes and input. There were a few [∅] realizations, mostly produced by an L2-advanced speaker who also demonstrated metalinguistic awareness of the dialect-specific allophone. The findings imply that advanced (L2 and heritage) speakers with favorable attitudes toward the local variety are most likely to demonstrate gradient language-specific allophonic changes during a short-term SA program.

The congruency effect—that is, faster and more accurate processing of congruent multiword units, has been demonstrated in multiple studies. It is still unclear, however, what its underlying mechanism is, and how congruency may interact with other factors. Using an acceptability judgement task, this study examined the congruency effect in immersive (Experiment 1) and nonimmersive (Experiment 2) L2 learners’ collocational processing while taking into account L2 collocation frequency, immersive learners’ L2 use, their length and starting age of immersion, nonimmersive learners’ length of instruction, and their L2 proficiency. The study also tested whether L1 counterparts of words in L2 collocations were activated. Nonmmersive learners showed a congruency effect in both processing speed and accuracy. In contrast, immersive learners were affected by congruency only in processing accuracy. Higher L2 collocation frequency, greater length of instruction, and higher L2 proficiency did not reduce the congruency effect, whereas longer duration of immersion improved the processing of incongruent items. An effect of L1 lexical frequency was found, an indication of L1 activation. Results were discussed in light of how L2 proficiency and experiences changed the amount of L1 influence in L2 collocational processing.

A second language can be learned inside and outside the classroom. In this study we investigated the English and French vocabulary knowledge of 110 Dutch-speaking children (age 10–12), who received 100 hours of instruction in French, whereas their contact with English came from out-of-school exposure only. We examined the role of individual differences (out-of-school exposure and gender) and word-related variables (cognateness, frequency, and language). The children completed a receptive vocabulary test in English and French and filled in a questionnaire. The results showed that the children had a larger vocabulary knowledge in English than in French, illustrating the power of contextual language learning. Word learning was influenced by the amount of exposure, word frequency, and cognateness. Additionally, English words were easier to learn than French words for the participants we tested. Our results point to the need for out-of-school exposure to supplement language learning in the classroom.

Bilingual language development might be characterized by transfer, deceleration, and/or acceleration, the first two being relevant for the language impairment diagnosis. Studies on bilingual children’s productive phonology show evidence of transfer, but little is known about deceleration in this population. Here, we focused on phonological transfer and deceleration in L1 speech of typically developing Polish-English bilingual children of Polish migrants to the United Kingdom (aged 4.7–7). We analyzed L1 speech samples of 30 bilinguals and 2 groups of Polish monolinguals, matched to the bilinguals on age or vocabulary size. We found that bilingual children’ speech (both simultaneous and early sequential) was characterized by transfer, but not by deceleration, suggesting that while phonological deceleration phases out in children above the age of 4.7, transfer does not. We discuss our findings within the PRIMIR model of bilingual phonological acquisition (Curtin et al., 2011) and show their implications for SLT practices.

This paper presents an experimental study of the rarely explored question of how input through instruction interacts with L2 acquisition at the level of modular linguistic knowledge. The investigation focuses on L2 knowledge of the English polarity item any, whose properties are only partially covered by typical language-teaching materials. We investigate Najdi-Saudi Arabic-speaking learners’ knowledge of the distribution of any in contexts that are taught, contexts that are not taught but may be observable in the input, and contexts that are neither taught nor observable. We further test whether conscious awareness of instructed rules about any correlates with performance. Our findings suggest a role for instruction and for internal, UG-constrained acquisition, and that these two paths interact. We explore our findings in terms of Sharwood Smith and Truscott’s (2014a, 2014b) framework of modular online growth and use of language, in which cognitive development is driven by processing.

In this study, neural representation of adult second language (L2) speakers’ implicit grammatical knowledge was investigated. Advanced L2 speakers of Japanese living in Japan, as well as L1 Japanese speakers, performed a word-monitoring task (proposed as an implicit knowledge test) in the MRI scanner. Behavioral measures were obtained from aptitude tests for explicit (language analytic ability) and implicit (statistical learning ability) learning. Findings indicate that, although both L1 and L2 speakers recruited neural circuits associated with procedural memory during the word-monitoring task, different brain regions were activated: premotor cortex (L1 speakers) and left caudate (L2 speakers). The premotor cortex activation was weaker in L2 than L1 speakers but was positively correlated with the left caudate activation, suggesting that their grammatical knowledge, while less automatized, was still developing. Behavioral sensitivity to errors was predicted only by explicit language aptitude, which may play a key role in the automatization of grammatical knowledge.

This study investigated the constructs underlying second language (L2) word association (WA) with regard to three dimensions of lexical competence—size, organization, and accessibility—and the lexical performance of speech. One-hundred and thirteen Japanese learners of English completed a computer-delivered oral WA task along with three vocabulary tasks: a form-recall gap-filling task (size), a primed lexical decision task (organization and accessibility), and an oral cartoon narrative (lexical richness). Regression analyses explored how well these lexical competence and performance scores predicted two WA outcome variables: response profiles and response times. Form-recall vocabulary knowledge, (collocational) priming, and lexical richness explained a large amount of variance in WA response type profiles (Nagelkerke’s pseudo R2 = .901). Form-recall vocabulary knowledge and lexical decision time explained 28.5% of the variance of WA response times. A three-stage model of L2 WA task performance is proposed to account for the constructs underlying WA performance.

We investigated how positive, negative, and neutral mood states influence aspects of second language acquisition, either directly or in interaction with certain personality characteristics (openness, intuition, emotional intelligence, foreign language anxiety, and impulsivity). After completing individual differences questionnaires, 120 participants were randomly assigned to either a Comparison group or one of three emotionally induced treatment groups. They were trained on a semiartificial language under incidental learning conditions. Immediate testing measured participants’ knowledge of the target syntactic forms, while source-attribution data gauged the nature (implicit, explicit, or a combination of both) of their knowledge. Contrary to some previous studies, knowledge gains were chiefly conscious-explicit. Participants exhibited substantial variability in how emotions impacted their learning, with self-reported stress management and premeditation resulting in higher learning in the Negative group. Overall, participants that claimed higher levels of intellect showed the best results.

To test the effects of talker variability and explicit instruction on the statistical learning of lexical tone, 80 monolingual English listeners were taught an artificial language that mimicked Mandarin’s asymmetric distribution of syllable-tone co-occurrences. Training stimuli consisted of either speech from one talker or speech from four talkers. Participants were either never instructed or explicitly taught associations between phonemes (CVs), tones, and nonce symbols across four consecutive days. Learning was assessed by the accuracy of mouse clicks and eye movements to visual nonce symbols. Critical trials induced competition between the target symbol, which matched the acoustic input, and a competitor symbol that had a statistically more probable tone (but mismatched the acoustic input). Eye fixations indicated that participants were sensitive to syllable-tone co-occurrence probabilities even without explicit instruction of tone. The degree to which statistical knowledge was used to recognize words appeared to increase when participants processed more variable speech.

We investigated age-related decline in adult learning of Dutch as an additional language (Ln) in speaking, writing, listening, and reading proficiency test scores for 56,024 adult immigrants with 50 L1s who came to the Netherlands for study or work. Performance for all four language skills turned out to decline monotonically after an age of arrival of about 25 years, similar to developmental trajectories observed in earlier aging research on additional language learning and in aging research on cognitive abilities. Also, linguistic dissimilarity increased age-related decline across all four language skills, but speaking in particular. We measured linguistic dissimilarity between first languages (L1s = 50) and Dutch (Ln) for morphology, vocabulary, and phonology. Our conclusion is that the L1 language background influences the effects of age-related decline in adult language learning, and that the constraints involved reflect both biological (language learning ability) and experience-based (acquired L1 proficiency) cognitive resources.

To investigate the skill transfer and the effects of practice schedules in the learning of second language syntax, 129 intermediate-level English learners were divided into six groups, based on practice format (input vs. output practice) and practice schedule (blocked vs. interleaved vs. hybrid [blocked + interleaved]). Analyses revealed that the learners tested on the skill they had practiced outperformed those who were tested on the nonpracticed skill. This pattern was particularly pronounced in comprehension processing speed and production accuracy. Moreover, hybrid practice facilitated skill development more than blocked or interleaved practice alone. Furthermore, a dynamic interplay was detected among practice format, schedule, and learners’ prior knowledge. Hybrid practice led to the least transfer from receptive skills (gained through input practice) to productive skills. Unlike interleaved practice effects, the effects of blocked practice on comprehension speed were more susceptible to learners’ prior processing speed.

Learners must develop the ability to perceive linguistic and social meaning in their second language (L2) to interact effectively, but relatively little is known about how learners link social meaning to a single phonetic variable. Using a matched-guise test targeting coda /s/ (realized as [s] or debuccalized [h]), we explore whether L2 Spanish learners identify native speakers’ social characteristics based on phonetic variants. Our results indicate that advanced learners were more sensitive to sociophonetic information; advanced listeners who had completed a phonetics course were significantly more likely to categorize /s/ reducers as Caribbean and those who had studied abroad in aspirating regions recognized a relationship between coda /s/ and status. To account for the complex interplay among proficiency, explicit instruction, and dialectal exposure in the development of L2 sociophonetic perception, we suggest the union of the L2 Linguistic Perception Model with exemplar models of phonological representation and indexical meaning.