We aimed to determine the electrophysiological correlates of incidental L2 word learning during dialogue, bridging memory and second language acquisition research in a realistic, but strictly controlled experimental paradigm. Native Dutch speakers of L2 English learned English words previously unknown to them (as confirmed in a ‘hidden’ pretest) through auditory input in a dialogue-like setting revolving around price comparisons, while we measured their EEG. Hearing an unknown as compared to a known word elicited an early and sustained negativity, as well as a later LPC that was actually predictive of subsequent learning success. Notably, in a second block, we found that ERPs to novel words that had just been learned in the previous block were already undistinguishable from those for known words, while not yet learned novel words still showed similar ERP signatures as in block 1. This lends support for a fast learning mechanism in adults incidentally ‘picking up’ new L2 words.

Research with nonnative speech spans many different linguistic branches and topics. Most studies include one or a few well-known features of a particular accent. However, due to a lack of empirical studies, little is known about how common these features are among nonnative speakers or how uncommon they are among native speakers. Moreover, it remains to be seen whether findings from such studies generalize to lesser-known features. Here, we demonstrate a quantitative approach to study nonnative accent features using Dutch-accented English as an example. By analyzing the phonetic distances between transcriptions of speech samples, this approach can identify the features that best distinguish nonnative from native speech. In addition, we describe a method to test hypotheses about accent features by checking whether the prevalence of the features overall varies between native and nonnative speakers. Furthermore, we include English speakers from the United States and United Kingdom and native Dutch speakers from Belgium and The Netherlands to address the issue of regional accent variability in both the native and target language. We discuss the results concerning three observed features. Overall, the results provide empirical support for some well-known features of Dutch-accented English, but suggest that others may be infrequent among nonnatives or in fact frequent among natives. In addition, the findings reveal potentially new accent features, and factors that may modulate the expression of known features. Our study demonstrates a fruitful approach to study nonnative accent features that has the potential to expand our understanding of the phenomenon of accent.

Anecdotal evidence suggests that learning a new foreign language (FL) makes you forget previously learned FLs. To seek empirical evidence for this claim, we tested whether learning words in a previously unknown L3 hampers subsequent retrieval of their L2 translation equivalents. In two experiments, Dutch native speakers with knowledge of English (L2), but not Spanish (L3), first completed an English vocabulary test, based on which 46 participant-specific, known English words were chosen. Half of those were then learned in Spanish. Finally, participants' memory for all 46 English words was probed again in a picture naming task. In Experiment 1, all tests took place within one session. In Experiment 2, we separated the English pre-test from Spanish learning by a day and manipulated the timing of the English post-test (immediately after learning vs. 1 day later). By separating the post-test from Spanish learning, we asked whether consolidation of the new Spanish words would increase their interference strength. We found significant main effects of interference in naming latencies and accuracy: Participants speeded up less and were less accurate to recall words in English for which they had learned Spanish translations, compared with words for which they had not. Consolidation time did not significantly affect these interference effects. Thus, learning a new language indeed comes at the cost of subsequent retrieval ability in other FLs. Such interference effects set in immediately after learning and do not need time to emerge, even when the other FL has been known for a long time.

While it is well established that grammar learning success varies with age, the cause of this developmental change is largely unknown. This study examined functional MRI activation across a broad developmental sample of 165 Dutch-speaking individuals (8-25 years) as they were implicitly learning a new grammatical system. This approach allowed us to assess the direct effects of age on grammar learning ability while exploring its neural correlates. In contrast to the alleged advantage of children language learners over adults, we found that adults outperformed children. Moreover, our behavioral data showed a sharp discontinuity in the relationship between age and grammar learning performance: there was a strong positive linear correlation between 8 and 15.4 years of age, after which age had no further effect. Neurally, our data indicate two important findings: (i) during grammar learning, adults and children activate similar brain regions, suggesting continuity in the neural networks that support initial grammar learning; and (ii) activation level is age-dependent, with children showing less activation than older participants. We suggest that these age-dependent processes may constrain developmental effects in grammar learning. The present study provides new insights into the neural basis of age-related differences in grammar learning in second language acquisition.

In this study, we explored the relationship between developmental differences in gray matter structure and grammar learning ability in 159 Dutch-speaking individuals (8 to 25 yr). The data were collected as part of a recent large-scale functional MRI study (Menks WM, Ekerdt C, Lemhöfer K, Kidd E, Fernández G, McQueen JM, Janzen G. Developmental changes in brain activation during novel grammar learning in 8-25-year-olds. Dev Cogn Neurosci. 2024;66:101347. https://doi.org/10.1016/j.dcn.2024.101347) in which participants implicitly learned Icelandic morphosyntactic rules and performed a grammaticality judgment task in the scanner. Behaviorally, Menks et al. (2024) showed that grammaticality judgment task performance increased steadily from 8 to 15.4 yr, after which age had no further effect. We show in the current study that this age-related grammaticality judgment task performance was negatively related to cortical gray matter volume and cortical thickness in many clusters throughout the brain. Hippocampal volume was positively related to age-related grammaticality judgment task performance and L2 (English) vocabulary knowledge. Furthermore, we found that grammaticality judgment task performance, L2 grammar proficiency, and L2 vocabulary knowledge were positively related to gray matter maturation within parietal regions, overlapping with the functional MRI clusters that were reported previously in Menks et al. (2024) and which showed increased brain activation in relation to grammar learning. We propose that this overlap in functional and structural results indicates that brain maturation in parietal regions plays an important role in second language learning.

While recent laboratory studies suggest that the use of competing languages is a driving force in foreign language (FL) attrition (i.e. forgetting), research on “real” attriters has failed to demonstrate such a relationship. We addressed this issue in a large-scale longitudinal study, following German students throughout a study abroad in Spain and their first six months back in Germany. Monthly, percentage-based frequency of use measures enabled a fine-grained description of language use. L3 Spanish forgetting rates were indeed predicted by the quantity and quality of Spanish use, and correlated negatively with L1 German and positively with L2 English letter fluency. Attrition rates were furthermore influenced by prior Spanish proficiency, but not by motivation to maintain Spanish or non-verbal long-term memory capacity. Overall, this study highlights the importance of language use for FL retention and sheds light on the complex interplay between language use and other determinants of attrition.

We investigate the role of awareness in learning non-salient grammar features in a second language during oral interaction. We conducted a learning experiment during which forty-eight adult Dutch-speaking advanced learners of German and a native German-speaking experimenter engaged in a scripted oral dialogue game. The experimenter and learner in turn produced sentences based on pictures eliciting German strong verbs with stem-vowel alternations, a morphosyntactic feature that represents a persistent learning difficulty. While learners in the implicit condition were merely instructed to focus on sentence meaning, learners in the explicit condition were encouraged to also pay attention to and learn from the target structure in the experimenter's input. Although the explicit group achieved higher accuracy scores overall, both groups had similar (absolute) learning gains, showing that oral input provided during interactive exchanges can lead to substantial learning not only under explicit, learning-targeted conditions, but also without an explicit directive to learn.

Multilinguals are impressive masters of flexibility. They can speak in only one language at a time without any apparent trouble, but also switch their languages easily if necessary. This apparent paradox has led researchers to ask whether multilinguals’ knowledge of their languages – such as the knowledge of words – is stored and accessed separately or together. This chapter summarizes what we currently know about the structure and workings of the tri- and multilingual lexicon, reviewing findings for word recognition, word production, and translation, as well as evidence from neurocognitive studies. It shows that the answer to the question how the trilingual mental lexicon is organized is not a simple, black-or-white one (i.e., ‘integrated’ or ‘separate’). Rather, the available evidence supports a nuanced view of trilingual word processing that is co-determined by characteristics of the individual and their acquisition history, the properties of the involved languages, and the nature of the task.

Background While it is well established that second language (L2) learning success changes with age and across individuals, the underlying neural mechanisms responsible for this developmental shift and these individual differences are largely unknown. We will study the behavioral and neural factors that subserve new grammar and word learning in a large cross-sectional developmental sample. This study falls under the NWO (Nederlandse Organisatie voor Wetenschappelijk Onderzoek [Dutch Research Council]) Language in Interaction consortium (website: https://www.languageininteraction.nl/ ). Methods We will sample 360 healthy individuals across a broad age range between 8 and 25 years. In this paper, we describe the study design and protocol, which involves multiple study visits covering a comprehensive behavioral battery and extensive magnetic resonance imaging (MRI) protocols. On the basis of these measures, we will create behavioral and neural fingerprints that capture age-based and individual variability in new language learning. The behavioral fingerprint will be based on first and second language proficiency, memory systems, and executive functioning. We will map the neural fingerprint for each participant using the following MRI modalities: T1‐weighted, diffusion-weighted, resting-state functional MRI, and multiple functional-MRI paradigms. With respect to the functional MRI measures, half of the sample will learn grammatical features and half will learn words of a new language. Combining all individual fingerprints allows us to explore the neural maturation effects on grammar and word learning. Discussion This will be one of the largest neuroimaging studies to date that investigates the developmental shift in L2 learning covering preadolescence to adulthood. Our comprehensive approach of combining behavioral and neuroimaging data will contribute to the understanding of the mechanisms influencing this developmental shift and individual differences in new language learning. We aim to answer: (I) do these fingerprints differ according to age and can these explain the age-related differences observed in new language learning? And (II) which aspects of the behavioral and neural fingerprints explain individual differences (across and within ages) in grammar and word learning? The results of this study provide a unique opportunity to understand how the development of brain structure and function influence new language learning success.

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The aim of this study was twofold: first, to develop an experimental technique as a tool to investigate learning outcomes of spontaneous, naturalistic second language (L2) learning under controlled laboratory conditions; and second, to explore how this technique can be used to understand the basic conditions and limits of this learning. Two variants of a dialogue game were tested in which corrective L2 input was provided to the learners, but the learning aspect was camouflaged. Participants were German learners of Dutch who are known to display persistent grammatical gender errors in Dutch owing to incorrect first language (L1)-L2 transfer. In Experiment 1, the participant and a 'virtual partner' (audio-recordings) took turns in describing cards using gender-marked article-noun phrases. However, the majority of the participants became aware of learning articles as goal of the experiment, either because of the way we asked participants about the goal of the experiment or because of the task used. Therefore, we changed both aspects and used a dialogue-memory game in Experiment 2, which indeed led only a minority (28%) to suspect the real goal of the study. In both experiments, participants showed substantial learning of word gender (on average 13.8 percentage points increase in accuracy) after only one instance of correct input. A manipulation of the number of trials (lag) between correct input and production did not affect results. Furthermore, the 72% of 'naïve' participants in Experiment 2 showed as much learning as the full sample. Thus, the new paradigm offers important insights into the determinants of naturalistic learning. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Foreign language attrition (FLA) appears to be driven by interference from other, more recently-used languages (Mickan et al., 2020). Here we tracked these interference dynamics electrophysiologically to further our understanding of the underlying processes. Twenty-seven Dutch native speakers learned 70 new Italian words over two days. On a third day, EEG was recorded as they performed naming tasks on half of these words in English and, finally, as their memory for all the Italian words was tested in a picture-naming task. Replicating Mickan et al. recall was slower and tended to be less complete for Italian words that were interfered with (i.e., named in English) than for words that were not. These behavioral interference effects were accompanied by an enhanced frontal N2 and a decreased late positivity (LPC) for interfered compared to not-interfered items. Moreover, interfered items elicited more theta power. We also found an increased N2 during the interference phase for items that participants were later slower to retrieve in Italian. We interpret the N2 and theta effects as markers of interference, in line with the idea that Italian retrieval at final test is hampered by competition from recently practiced English translations. The LPC, in turn, reflects the consequences of interference: the reduced accessibility of interfered Italian labels. Finally, that retrieval ease at final test was related to the degree of interference during previous English retrieval shows that FLA is already set in motion during the interference phase, and hence can be the direct consequence of using other languages.

While the tendency of speakers to align their speech to that of others acoustic-phonetically has been widely studied among native speakers, very few studies have examined whether natives phonetically converge to non-native speakers. Here we measured native Dutch speakers' convergence to a non-native speaker with an unfamiliar accent in a novel non-interactive task. Furthermore, we assessed the role of participants' perceptions of the non-native accent in their tendency to converge. In addition to a perceptual measure (AXB ratings), we examined convergence on different acoustic dimensions (e.g., vowel spectra, fricative CoG, speech rate, overall f0) to determine what dimensions, if any, speakers converge to. We further combined these two types of measures to discover what dimensions weighed in raters' judgments of convergence. The results reveal overall convergence to our non-native speaker, as indexed by both perceptual and acoustic measures. However, the ratings suggest the stronger participants rated the non-native accent to be, the less likely they were to converge. Our findings add to the growing body of evidence that natives can phonetically converge to non-native speech, even without any apparent socio-communicative motivation to do so. We argue that our results are hard to integrate with a purely social view of convergence.

Internal error monitoring as reflected by the error-related negativity (ERN) component can give insight into the process of learning a second language (L2). Yet, early stages of learning are characterized by high levels of uncertainty, which obscures the process of error detection. We examine how uncertainty about L2 syntactic representations, induced by different levels of language conflict, is reflected in ERN patterns during learning. German learners of Dutch performed a feedback-guided gender decision task in their L2 and provided subjective certainty ratings for their responses. Initially, high-conflict items yielded more uncertainty and ERN modulations were reversed (i.e., correct responses elicited larger amplitudes than errors). Two rounds of feedback resulted in an increase of accuracy, reduced uncertainty, and normalization of the ERN effect, signaling effective error monitoring. These outcomes demonstrate how subjective intuitions about response accuracy affect performance monitoring during L2 learning.

Bilingual speakers have to control their languages to avoid interference, which may be achieved by enhancing the target language and/or inhibiting the nontarget language. Previous research suggests that bilinguals use inhibition (e.g., Jackson et al., 2001), which should be reflected in the N2 component of the event-related potential (ERP) in the EEG. In the current study, we investigated the dynamics of inhibitory control by measuring the N2 during language switching and repetition in bilingual picture naming. Participants had to name pictures in Dutch or English depending on the cue. A run of same-language trials could be short (two or three trials) or long (five or six trials). We assessed whether RTs and N2 changed over the course of same-language runs, and at a switch between languages. Results showed that speakers named pictures more quickly late as compared to early in a run of same-language trials. Moreover, they made a language switch more quickly after a long run than after a short run. This run-length effect was only present in the first language (L1), not in the second language (L2). In ERPs, we observed a widely distributed switch effect in the N2, which was larger after a short run than after a long run. This effect was only present in the L2, not in the L1, although the difference was not significant between languages. In contrast, the N2 was not modulated during a same-language run. Our results suggest that the nontarget language is inhibited at a switch, but not during the repeated use of the target language.

One challenge of learning a foreign language (L2) in adulthood is the mastery of syntactic structures that are implemented differently in L2 and one's native language (L1). Here, we asked how L2 speakers learn to process syntactic constructions that are in direct conflict between L1 and L2, in comparison to structures without such a conflict. To do so, we measured EEG during sentence reading in three groups of German learners of Dutch with different degrees of L2 experience (from 3 to more than 18 months of L2 immersion) as well as a control group of Dutch native speakers. They read grammatical and ungrammatical Dutch sentences that, in the conflict condition, contained a structure with opposing word orders in Dutch and German (sentence-final double infinitives) and, in the no-conflict condition, a structure for which word order is identical in Dutch and German (subordinate clause inversion). Results showed, first, that beginning learners showed N400-like signatures instead of the expected P600 for both types of violations, suggesting that, in the very early stages of learning, different neurocognitive processes are employed compared with native speakers, regardless of L1-L2 similarity. In contrast, both advanced and intermediate learners already showed native-like P600 signatures for the no-conflict sentences. However, their P600 signatures were significantly delayed in processing the conflicting structure, even though behavioral performance was on a native level for both these groups and structures. These findings suggest that L1-L2 word order conflicts clearly remain an obstacle to native-like processing, even for advanced L2 learners.

Internal error monitoring as reflected by the error-related negativity (ERN) component can give insight into the process of learning a second language (L2). Yet, early stages of learning are characterized by high levels of uncertainty, which obscures the process of error detection. We examine how uncertainty about L2 syntactic representations, induced by different levels of language conflict, is reflected in ERN patterns during learning. German learners of Dutch performed a feedback-guided gender decision task in their L2 and provided subjective certainty ratings for their responses. Initially, high-conflict items yielded more uncertainty and ERN modulations were reversed (i.e., correct responses elicited larger amplitudes than errors). Two rounds of feedback resulted in an increase of accuracy, reduced uncertainty, and normalization of the ERN effect, signaling effective error monitoring. These outcomes demonstrate how subjective intuitions about response accuracy affect performance monitoring during L2 learning.

Bilinguals usually select the right language to speak for the particular context they are in, but sometimes the nontarget language intrudes. Despite a large body of research into language selection and language control, it remains unclear where intrusion errors originate from. These errors may be due to incorrect selection of the nontarget language at the conceptual level, or be a consequence of erroneous word selection (despite correct language selection) at the lexical level. We examined the former possibility in two language switching experiments using a manipulation that supposedly affects language selection on the conceptual level, namely whether the conversational language context was associated with the target language (congruent) or with the alternative language (incongruent) on a trial. Both experiments showed that language intrusion errors occurred more often in incongruent than in congruent contexts, providing converging evidence that language selection during concept preparation is one driving force behind language intrusion.

In 3 ERP experiments, we investigated how experienced L2 speakers process natural and correct syntactic input that deviates from their own, sometimes incorrect, syntactic representations. Our previous study (Lemhöfer, Schriefers, & Indefrey, 2014) had shown that L2 speakers do engage in native-like syntactic processing of gender agreement but base this processing on their own idiosyncratic (and sometimes incorrect) grammars. However, as in other standard ERP studies, but different from realistic L2 input, the materials in that study contained a large proportion of incorrect sentences. In the present study, German speakers of Dutch read exclusively objectively correct Dutch sentences that did or did not contain subjective determiner "errors" (e.g., de boot "the boat," which conflicts with the intuition of many German speakers that the correct phrase should be het boot). During reading for comprehension (Experiment 1), no syntax-related ERP responses for subjectively incorrect compared to correct phrases were observed. The same was true even when participants explicitly attended to and learned from the determiners in the sentences (Experiment 2). Only when participants judged the correctness of determiners in each sentence (Experiment 3) did a clear P600 appear. These results suggest that the full and native-like use of subjective grammars, as reflected in the P600 to subjective violations, occurs only when speakers have reason to mistrust the grammaticality of the input, either because of the nature of the task (grammaticality judgments) or because of the salient presence of incorrect sentences. (PsycInfo Database Record (c) 2020 APA, all rights reserved).