Cunnings' keynote offers a new perspective on L2 processing by casting L1–L2 differences in terms of the memory system. One advantage of this approach is that it makes use of cue-based memory retrieval, a framework that has given rise to a wealth of research on L1 processing. However, there remain some questions about the evidence-base and predictions of the account, as well as conceptual challenges to its implementation.

Previous research has suggested that the advantages for cognitive control abilities in bilinguals are attenuated when socio-economic status (SES) is controlled (e.g., Morton & Harper, 2007). This study examined the effect of SES on cognitive control in illiterate monolingual and bilingual individuals who lived in adverse social conditions. We tested monolinguals and bilinguals using Simon and Attentional Network task while controlling for two potential confounding factors: SES and literacy. Bilinguals were faster for both trials with and without conflict demonstrating overall faster response times (global advantage) compared to monolinguals on both tasks. However, no bilingual advantage was found for conflict resolution on the Simon task and attentional networks on the Attentional Network task. The overall bilingual effects provide evidence for a bilingual advantage even among individuals without literacy skills and of very low SES. This indicates a strong link between bilingualism and cognitive control over and above effects of SES.

Carroll's paper (Carroll) is most welcomed and shows that the weaker language is still to be explored from various points of views. Over twenty years after the publication of Schlyter's paper, “The weaker language in bilingual Swedish-French children”, not only is the topic of the weaker language of simultaneous bilinguals still a clearly under-researched area, but it is also, as Carroll shows, a crucial domain of research in the discussion of properties and constraints of the human Language Making Capacity (LMC).

In this study we explore whether world knowledge (WK) processing differs between individuals listening to their native (L1) or their non-native (L2) language. We recorded event-related brain potentials in L1 and L2 speakers of Spanish while they listened to sentences uttered by native speakers of Spanish. Sentences were either congruent or incongruent with participants’ WK. In addition, participants also listened to sentences in which upcoming words could not be anticipated on the basis of WK. WK violations elicited a late negativity of greater magnitude and duration in the L2 than the L1 group. However, sentences in which WK was not helpful regarding word anticipation elicited similar N400 modulations in both groups. These results suggest that WK processing requires a deeper lexical search in L2 comprehension than in L1 comprehension.

Although many studies have investigated the consequences of bilingualism on cognitive control, few have examined the impact of bilingualism on other cognitive domains, such as memory. Of these studies, most have focused on item memory and none have examined the role of bilingualism in source memory (i.e., the memory for contextual details from a previous encounter with a stimulus). In our study, young adult bilinguals and monolinguals completed a source memory test, whose different conditions were designed to stress working memory and inhibitory control. Bilinguals performed significantly faster than monolinguals across all conditions without compromising accuracy, and also showed an overall speed advantage on the Flanker task. We interpret these processing speed advantages within the context of current models of bilingual production.

What is the time course of cross-language activation in deaf sign–print bilinguals? Prior studies demonstrating cross-language activation in deaf bilinguals used paradigms that would allow strategic or conscious translation. This study investigates whether cross-language activation can be eliminated by reducing the time available for lexical processing. Deaf ASL–English bilinguals and hearing English monolinguals viewed pairs of English words and judged their semantic similarity. Half of the stimuli had phonologically related translations in ASL, but participants saw only English words. We replicated prior findings of cross-language activation despite the introduction of a much faster rate of presentation. Further, the deaf bilinguals were as fast or faster than hearing monolinguals despite the fact that the task was in their second language. The results allow us to rule out the possibility that deaf ASL–English bilinguals only activate ASL phonological forms when given ample time for strategic or conscious translation across their two languages.

In the current study, we investigated bilingual error detection by measuring the repair rate of language intrusions (i.e., involuntary production of nontarget language words) that arose while bilinguals produced sentences in a language switching context. This allowed us to compare two prominent accounts of error detection in a bilingual setting. According to the conflict monitoring account, error detection is initiated by interference. Since language switching increases bilingual language interference, error detection should be better in switch relative to repetition trials. According to the perceptual loop theory, error detection is based on language comprehension. Since language switching is known to impair language comprehension, it follows that error detection should be worse in switch relative to repetition trials. The results showed that the repair rate of language intrusions was higher in switch than repetition trials, thus providing evidence that bilingual language interference instigates error detection, in line with the conflict monitoring account.

Carroll's critique (Carroll) of the field of bilingualism yields strong directives. Let us not study specific groups of bilinguals, and make big claims about bilingual learning. Let us not study one domain, say vocabulary, and generalize to bilinguals’ language. These are all valid points. She also voices strong skepticism about how current literature deals with language experience:

Cunnings (2016) provides welcome insights into differences between native speaker (NS) sentence processing, adult non-native speaker processing (NNS), and working memory capacity (WMC) limitations. This commentary briefly raises three issues: construct operationalization; the role of first language (L1); and context.

One hundred and sixty-eight young adult participants were classified as monolingual or bilingual and as having a previously reported clinical diagnosis of ADHD or not to create four groups. All participants completed tests of language proficiency, ADHD ratings, and executive control. Both bilingualism and ADHD are generally associated with poorer vocabulary knowledge, but bilingualism and ADHD are associated with opposite effects on executive control. Consistent with this literature, bilinguals performed more poorly than monolinguals on the vocabulary test but contrary to predictions, the ADHD group performed somewhat better on language ability than the non-ADHD group, attesting to their high functioning status. For the flanker task, both bilinguals and non-ADHD participants showed less cost in performing in the conflict condition than in the baseline condition. For the stop-signal task, ADHD status interfered more with performance by bilinguals than monolinguals, suggesting a greater burden of ADHD on executive function for this group.

This study investigates how beginner and advanced Dutch learners of Mandarin process tonal information. An ABX task was adopted to investigate phonological discrimination of Mandarin tones and segment-tone integration in Dutch learners of Mandarin, with both native Mandarin and Dutch speakers (without tonal learning experience) as control groups. Results showed a developmental path in lexical tone processing. The beginner learners could not process tonal contrast adequately at the phonological level, and they processed segmental and tonal information separately, like native Dutch listeners without Mandarin experience. The advanced learners showed a good phonological discrimination of tonal contrasts. They showed a more native-like pattern in distributing their attention between segmental and tonal information, and they processed the two dimensions in an integrated manner, similar to native Mandarin listeners. This suggests that the acquisition of new tonal categories in L2 involves a redistribution of attention along perceptual dimensions and the development of segment-tone integration.

Exposure and input are often used interchangeably in the study of child bilingualism to describe the learner's interaction with her environment. Carroll (Carroll), in her thought-provoking keynote article, challenges the equation between amount of exposure and amount of input necessary for acquiring a language, and in particular a second language. Carroll, whose diverse research borrows from both generative and psychological models of learning, brings these two perspectives into her exploration of the role of exposure and input in language acquisition, calling for a clearer definition of each. Carroll argues that the input to the language acquisition mechanism is the abstract construct necessary in order to solve the learning problem, and it is not a function of the amount of exposure: very little input is necessary in order to solve a learning problem, e.g., identifying word boundaries, or acquiring a syntactic structure. While scrutinizing the equation often drawn between exposure and input, Carroll further argues that the amount of exposure further misses the quality of this exposure as well as the societal context in which this exposure occurs.

This study investigated the phonological preparation unit when planning spoken words with native Chinese speakers who speak English as a Second Language (ESLs). In Experiment 1, native Chinese speakers named pictures in Chinese, and the names shared the same onset, same rhyme, or had nothing systematically in common. No onset effect was shown, suggesting that native Chinese speakers did not use onset as their preparation unit. There was a rhyme interference effect, probably due to lexical competition. In Experiment 2, the same task was conducted in English among Chinese ESLs and native English speakers. Native speakers showed onset facilitation whereas ESLs did not show such an effect until Block 3. ESLs’ phonological preparation unit is likely to be influenced by their native language but with repetition they are able to attend to sub-syllabic units. Both groups showed rhyme interference, possibly as a result of joint lexical and phonological competition.

Previous research has indicated that bilinguals outperform monolinguals in cognitive tasks involving spatial working memory. The present study examines evidence for this claim using a different and arguably more ecologically valid method (the change blindness task). Bilingual and monolingual participants were presented with two versions of the same scenes and required to press a key as soon as they identified the alteration. They also completed the word and alpha span tasks, and the Corsi blocks task. The results in the change blindness task, controlled for group differences in non-verbal reasoning, indicated that bilinguals were faster and more accurate than monolinguals at detecting visual changes. Similar group differences were found on the Corsi block task. Unlike previous findings, no group differences were found on the verbal memory tasks. The results are discussed with reference to mechanisms of cognitive control as a locus of transfer between bilingualism and spatial working memory tasks.

Over the years, models proposed for second-language (L2) processing have been remarkably parallel to those proposed for Broca's aphasia. Differences between agrammatic and unaffected language processing have been explained, e.g., in terms of lack of detailed syntactic structure building (Grodzinsky, 1995), resource deficits (Haarman, Just & Carpenter, 1997), slow syntactic processing (Burkhardt, Avrutin, Piñango & Ruigendijk, 2008), or slowed lexical access (Love, Swinney, Walenski & Zurif, 2008). Each of these approaches have their homolog in L2 processing (e.g., Clahsen & Felser, 2006; McDonald, 2006; Dekydtspotter, Schwartz & Sprouse, 2006; Hopp, 2013, respectively). It is therefore not surprising that Cunnings's proposal (Cunnings, 2016) parallels another idea in aphasia and aging research, namely that deviations from healthy young adult monolingual sentence processing can be attributed to an increased susceptibility to interference (e.g., Sheppard, Walenski, Love & Shapiro, 2015).

Long-term experience with a tonal language shapes pitch perception in specific ways, and consequently Chinese speakers may not process pitch in English words – e.g., “Rose?” spoken as a question versus “Rose” spoken as a statement – in the same way as native speakers of non-tonal languages do. If so, what are those pitch processing differences and how do they affect Chinese recognition of English words? We investigated these questions by administering a primed lexical-decision task in English to proficient Chinese–English bilinguals and two control groups, namely, Spanish–English and native English speakers. Prime-target pairs differed in one sound and/or in pitch. Results showed specific cross-language differences in pitch processing between the Chinese speakers and the control groups, confirming that experience with a tonal language shaped the perception of English words' intonation. Moreover, such experience helps to incorporate pitch into models of word-recognition for bilinguals of tonal and non-tonal languages.

The question of interest in this study was whether bilingual individuals show superior executive control compared to monolingual participants. Findings are mixed, with studies showing advantage, disadvantage, or no difference between bilingual and monolingual speakers. In this study, we used different experimental conditions to examine implicit learning, resistance to interference, monitoring, and switching, independently. In addition, we matched our monolingual and bilingual participants on baseline response time. Bilingual participants demonstrated faster implicit learning, greater resistance to interference, more efficient switching compared to monolingual participants. The groups did not differ in monitoring. In conclusion, depending on task complexity and on the target executive control component, there are different patterns of bilingual advantage, beyond the global faster processing speed documented in previous studies. Bilingual young adults showed more efficient adjustments of the cognitive system in response to changes in task demands.

Based on a detailed review of existing studies of high-proficiency second-language (L2) learners who acquired the L2 in adolescence/adulthood, Cunnings (Cunnings, 2016) argues that Sorace's (2011) Interface Hypothesis (IH) and Clahsen and Felser's (2006) Shallow Structure Hypothesis (SSH) do not explain the existing data as well as his memory-based approach which posits that memory-retrieval processes in the L1 and L2 do not pattern alike. Cunnings proposes that L1 and L2 processing differ in terms of comprehenders’ ability to retrieve from memory information constructed during sentence processing. He concludes that L2 processing is more susceptible to interference effects during retrieval, and, most relevantly for this commentary, that discourse-based cues to memory retrieval are more heavily weighted in L2 than L1 processing.

At its best, the field of bilingualism is a dynamic discipline informed by diverse perspectives. Carroll's critical review – situated within a linguistics framework – contends that current research on bilingual exposure and language development suffers from a lack of theoretical clarity, and makes little contribution to our understanding of bilingual acquisition. Carroll's push (Carroll) towards greater precision in our thinking about the relation between input and outcomes is an important and welcome challenge. However, it is also critical to keep in mind the social context that motivates much of the current research on bilingual development, and to leave room for studies whose main goal is to provide answers to societally important questions about bilingual children's health and development.

The effects of exposure to non-English heritage languages versus exposure to foreign-accented English during early childhood on language performances later in life were investigated. Three groups of young adult participants who differed in their early home language environment were examined on a series of linguistic tasks. Results showed that people who were mostly exposed to accented English in the early home environment are more native-like in various aspects of English language performance than those who were mostly exposed to their non-English heritage language, including vocabulary, pronunciation, and processing of certain types of speech stimuli. Early and extended exposure to accented speech, however, does not appear to enhance the ability to perceive foreign accents in general, and may in fact produce a disadvantage when listening to unfamiliar accents. These findings provide some initial insight into the consequences of migrant parents choosing to speak one language over the other with their children.