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).

To begin with, we thank the commentators for their remarks, which both intrigued and challenged us in various ways. Time and space limits prevent us from doing justice to all the points they raised, so we will focus on those we consider most significant and are best prepared to deal with. One of these points, of course, is the overall character and status of our proposal. Pienemann terms Acquisition by Processing (APT) ‘an interesting point of departure’ (p. 38) for the development of a theory of acquisition and processing. Harrington and Carroll say in effect that it can't be done; others seem more open to the possibility. In any case, we quickly accept Roeper's suggestion that what we have presented is more a ‘prole-gomena’ (p. 21) to a theory than a full-fledged theory in itself.

Most cognate research suggests facilitation effects in picture naming, but how these effects manifest in bilinguals after brain damage remains unclear. Additionally, whether this effect is captured in clinical measures is largely unknown. Using data from the Boston Naming Test, we examined the naming of cognates and noncognates, the extent of cognate facilitation produced, and the individual differences in bilingual language experience associated with naming outcomes in forty Spanish–English bilingual persons with aphasia (BPWA) relative to thirty-one Spanish–English healthy bilinguals (HB). Results suggest that naming performance in L1 and L2 in both groups is modulated by lexical frequency, bilingual language experience, and by language impairment in BPWA. Although the two groups showed similarities, they deviated in benefit drawn from the extent of phoneme/grapheme overlap in cognate items. HB showed an association between cognate facilitation and bilingual language experience, while cognate facilitation in BPWA was only associated with L2 language impairment.

Previous research has demonstrated that individual differences in conflict management predict second-language (L2) reading skill. The current experiment tested the hypothesis that this relation reflects the need to manage conflict from cross-linguistic interactions (CLI). A novel model specifying the relation between L2 reading skill, CLI, and the predictors of such interactions was tested in 253 L2 English speaking adults, using structural equation modeling. In support of the hypothesis, the findings revealed that stronger CLI was related to poorer L2 reading skill. In addition, variability in non-linguistic conflict management, as measured by executive attention tasks, and relative language dominance reliably predicted CLI. Specifically, better conflict management and lower L1 dominance corresponded to fewer interactions. These results fill a crucial gap by demonstrating for the first time that the ability to manage CLI is critical to L2 reading, and that both cognitive skills and language experience contribute to variability in these interactions.

The study of bilingual development has been, and must be, an interdisciplinary endeavor; Carroll (Carroll) presents us with a perspective from within one particular discipline, that of generative linguistics. From this vantage point, she provides us perhaps most importantly with the reminder that language is not a unitary construct, and cautions against extrapolating from findings on the learning of one particular aspect of language, such as vocabulary, to language acquisition more broadly. I wholeheartedly agree (for a similar point, see Paradis & Grüter, 2014). I do not agree, however, with Carroll's implication that such unwarranted extrapolation is characteristic of current research on input and bilingual development. A number of recent studies have looked specifically at the differential relation between input (in a wide sense) and bilingual children's acquisition of different linguistic phenomena. Unsworth (2014), for example, reported different effects of input variation on Dutch–English bilingual children's acquisition of grammatical gender versus indefinite object scrambling.

If one asks how many languages there are, one can imagine at least three answers: one, over six billion, or 7,358.

In the recent swell of research on bilingualism and its consequences for the mind and the brain, there has been a warning that we need to remember that not all bilinguals are the same (e.g., Green & Abutalebi, 2013; Kroll & Bialystok, 2013; Luk & Bialystok, 2013). There are bilinguals who acquired two languages in early childhood and have used them continuously throughout their lives, bilinguals who acquired one language early and then switched to another language when they entered school or emigrated from one country to another, and others who only acquired a second language (L2) as an adult. Among these forms of bilingualism there are differences in both the context and amount of time spent in each language and differences in the status of the languages themselves. The L2 may be a majority language, spoken by almost everyone in the environment, or a minority language, spoken only by a few. The native or first language (L1) may also be the dominant language or may have been overtaken by the influence of the L2 given the circumstances imposed by the environment. Likewise, the L1 and L2 may vary in how similar they are structurally, whether they share the same written script, or whether one language is spoken and the other signed.

Child language researchers have often assumed that progress in first language learning depends heavily on language exposure. For example, Hart and Risley (1995) compared children in middle class families with children in lower class families. Based on recordings made across several years in the home, they estimated that by the time the children from lower SES families entered first grade they had heard 30 million fewer words than the middle class children. Researchers and educators have argued that this ‘30 million word gap’ is a primary cause for academic failure of lower SES children in the primary grades in the United States. Researchers in second language acquisition (SLA) research have often postulated a similar linkage between exposure and attainment, both for early and simultaneous bilingual children and later second language learning. Carroll (Carroll) expresses justifiable skepticism regarding such claims regarding the effect of amount of exposure on language attainment. Despite some important differences in conceptualization of the nature of the input, I find her overall analysis compelling and important.

How are the two lexicons of a bilingual represented and how do they interact during language processing? These questions are central to bilingualism and have been the topics of a large number of studies. Dijkstra, Wahl, Buytenhuijs, van Halem, Al-jibouri, De Korte & Rekke (in press) put forward a model that tries to capture people's behavior in several tasks mostly involving reading, with the exception of word translation. A praise-worthy feature of the model is that it is computationally implemented following a local-connectionist architecture. The model is then used to quantitatively account for reaction time patterns on various tasks, with considerable success.

We investigated whether fluent language production is associated with greater skill in resolving lexical competition during spoken word recognition and ignoring irrelevant information in non-linguistic tasks. Native English monolinguals and native English L2 learners, who varied on measures of discourse/verbal fluency and cognitive control, identified spoken English words from dense (e.g., BAG) and sparse (e.g., BALL) phonological neighborhoods in moderate noise. Participants were slower in recognizing spoken words from denser neighborhoods. The inhibitory effect of phonological neighborhood density was smaller for English monolinguals and L2 learners with higher speech production fluency, but was unrelated to cognitive control as indexed by performance on the Simon task. Converging evidence from within-language effects in monolinguals and cross-language effects in L2 learners suggests that fluent language production involves a competitive selection process that may not engage all domain-general control mechanisms. Results suggest that language experience may capture individual variation in lexical competition resolution.

Four bilingual speakers of Irish (Gaelic) and English, two men and two women, were audiorecorded as they produced narratives based on pictures from the Mercer Mayer book Frog, where are you? Order of narration was counterbalanced. The narratives were analyzed according to certain features of global and local structure originally identified in Berman and Slobin (1994). Differences within and across narratives emerged in the number of components included, the number of planning components explicitly marked for purpose, the marking of tense and aspect, and the use of extended aspectual categories. These variations were attributed to 1) the order in which the narrative was told (first-told versus second-told versions), 2) the language of the narrative (Irish versus English), and 3) the particular preferences of individual narrators.

Four hypotheses regarding the impact of discourse context on cross-language lexical activation were tested. Highly-proficient, Spanish–English bilinguals read all-English paragraphs containing non-identical and identical cognates or noncognate controls while their eye-movements were tracked. There were four paragraph conditions based on a full crossing of semantic bias from the topic sentence and sentence containing the critical word. In analyses in which cognate status was treated categorically there was an interaction between global bias and cognates status such that the observed inhibitory effects of cognate status were attenuated in global-neutral contexts. Follow-up analyses on the non-identical cognates in which orthographic overlap was treated continuously revealed a U-shaped function between orthographic overlap and processing time, which was more pronounced in global-neutral contexts. The overall pattern of findings is consistent with a combined operation of resonant-based and feature-restriction mechanisms of context effects.

There exists insufficient eye-tracking evidence on the differences in emotional word processing between the first language (L1) and second language (L2) readers. This study conducted an eye-tracking experiment to investigate the emotional effects in L2 sentence reading, and to explore the modulation of L2 proficiency and individual emotional states. Adapted from Knickerbocker et al. (2015), the current study recorded eye movements at both early and late processing stages when late Chinese–English bilinguals read emotion-label and neutral target words in natural L2 sentences. Results indicated that L2 readers did not show the facilitation effects of lexical affective connotations during sentence reading, and they even demonstrated processing disadvantages for L2 emotional words. Additionally, the interaction effect between L2 proficiency and emotion was consistently significant for the measure of total reading time in positive words. Measurements of participants’ depressive and anxious states were not robustly correlated with eye movement measures. Our findings supplemented new evidence to existing sparse eye-tracking experiments on L2 emotion processing, and lent support to several theoretical frameworks in the bilingual research field, including the Emotional Contexts of Learning Theory, Lexical Quality Hypothesis and Revised Hierarchical Model.

The present study provides insight into cross-language activation in hearing bimodal bilinguals by (1) examining co-activation of spoken words during processing of signs by hearing bimodal bilingual users of Dutch (their L1) and Sign Language of the Netherlands (NGT; late learners) and (2) investigating the contribution of mouthings to bimodal cross-language activation. NGT signs were presented with or without mouthings in two sign-picture verification experiments. In both experiments the phonological relation (unrelated, cohort overlap or final rhyme overlap) between the Dutch translation equivalents of the NGT signs and pictures was manipulated. Across both experiments, the results showed slower responses for sign-picture pairs with final rhyme overlap relative to phonologically unrelated sign-picture pairs, indicating co-activation of the spoken language during sign processing, but no significant effect for sign-picture pairs with cohort overlap in Dutch. In addition, co-activation was not affected by the presence or absence of mouthings.

Most English compounds are spaced compounds, whereas spelling regulations prescribe Finnish compounds to be written in a concatenated format. However, as in English, Finnish compounds are commonly spaced nowadays (e.g., piha juhla ‘garden party’), a phenomenon that we labeled the ‘English disease’. In this eye movement study with Finnish–English bilinguals we investigate whether the reading of a concatenated or illegally spaced Finnish compound is affected by the spelling of an English translation equivalent (ETE). We found that spaced Finnish compounds were read slower than their concatenated counterparts, but this effect was attenuated when ETEs were thought to be spaced. Similarly, concatenated Finnish compounds were read faster when their ETEs were also concatenated. These backward transfer effects are in line with studies that show that processing behavior in L1 is affected by a strong concurrent L2, even when the L1 is the native language as well as the dominant community language.

Structural and functional brain adaptations in bilingual speakers are well documented in the neurolinguistic literature. However, far less is known about neural changes evidenced in multilingual speakers. This study investigates brain plasticity in a group of highly proficient multilinguals, fluent in four or more languages, compared to a group of monolinguals. An ROI analysis used to evaluate differences in core linguistic regions and regions associated with language control revealed robust decreases for multilinguals in grey matter thickness of two brain regions within the parietal lobe (i.e., precuneus and angular gyrus), involved in lexico-semantic processing, memory retrieval, and control maintenance. We discuss our findings in the context of emerging models characterizing trajectorial changes in brain structures associated with language experience. We consider how the demands of optimal functioning within multi-linguistic environments may foster cortical changes that manifest as decreased GM thickness in highly proficient multilingual compared to monolinguals.

Bilingualism is thought to confer advantages in executive functioning, thereby contributing to cognitive reserve and a later age of dementia symptom onset. While the relation between bilingualism and age of onset has been explored in Alzheimer's dementia, there are few studies examining bilingualism as a contributor to cognitive reserve in frontotemporal dementia (FTD). In line with previous findings, we hypothesized that bilinguals with behavioral variant FTD would be older at symptom onset compared to monolinguals, but that no such effect would be found in patients with nonfluent/agrammatic variant primary progressive aphasia (PPA) or semantic variant PPA. Contrary to our hypothesis, we found no significant difference in age at symptom onset between monolingual and bilingual speakers within any of the FTD variants, and there were no notable differences on neuropsychological measures. Overall, our results do not support a protective effect of bilingualism in patients with FTD-spectrum disease in a U.S. based cohort.