Publications

Abstract

This study investigated how bilingual experience alters neural mechanisms supporting novel word learning. We hypothesised that novel words elicit increased semantic activation in the larger bilingual lexicon, potentially stimulating stronger memory integration than in monolinguals. English monolinguals and Spanish–English bilinguals were trained on two sets of written Swahili–English word pairs, one set on each of two consecutive days, and performed a recognition task in the MRI-scanner. Lexical integration was measured through visual primed lexical decision. Surprisingly, no group difference emerged in explicit word memory, and priming occurred only in the monolingual group. This difference in lexical integration may indicate an increased need for slow neocortical interleaving of old and new information in the denser bilingual lexicon. The fMRI data were consistent with increased use of cognitive control networks in monolinguals and of articulatory motor processes in bilinguals, providing further evidence for experience-induced neural changes: monolinguals and bilinguals reached largely comparable behavioural performance levels in novel word learning, but did so by recruiting partially overlapping but non-identical neural systems to acquire novel words.

Abstract

Children who have knowledge of two languages may show better phonological awareness than their monolingual peers (e.g. Bruck & Genesee, 1995). It remains unclear how much bilingual experience is needed for such advantages to appear, and whether differences in language or cognitive skills alter the relation between bilingualism and phonological awareness. These questions were investigated in this cross-sectional study. Participants (n = 294; 4–7 year-olds, in the first three grades of primary school) were Dutch-speaking pupils attending mainstream monolingual Dutch primary schools or early-English schools providing English lessons from grade 1, and simultaneous Dutch-English bilinguals. We investigated phonological awareness (rhyming, phoneme blending, onset phoneme identification, and phoneme deletion) and its relation to age, Dutch vocabulary, English vocabulary, working memory and short-term memory, and the balance between Dutch and English vocabulary. Small significant (α < .05) effects of bilingualism were found on onset phoneme identification and phoneme deletion, but post-hoc comparisons revealed no robust pairwise differences between the groups. Furthermore, effects of bilingualism sometimes disappeared when differences in language or memory skills were taken into account. Learning two languages simultaneously is not beneficial to – and importantly, also not detrimental to – phonological awareness.

Abstract

This study investigated to what extent the Peabody Picture Vocabulary Test
(PPVT-4) is a reliable tool for measuring vocabulary knowledge of English as
a second language (L2), and to what extent L1 characteristics affect test
outcomes. The PPVT-4 was administered to Dutch pupils in six different
age groups (4-15 years old) who were or were not following an English
educational programme at school. Our first finding was that the PPVT-4
was not a reliable measure for pupils who were correct on maximally 24
items, but it was reliable for pupils who performed better. Second, both
primary-school and secondary-school pupils performed better on items
for which the phonological similarity between the English word and its
Dutch translation was higher. Third, young unexperienced L2 learners’
scores were predicted by Dutch lexical frequency, while older more
experienced pupils’ scores were predicted by English frequency. These
findings indicate that the PPVT may be inappropriate for use with L2
learners with limited L2 proficiency. Furthermore, comparisons of PPVT
scores across learners with different L1s are confounded by effects of L1
frequency and L1-L2 similarity. The PPVT-4 is however a suitable measure
to compare more proficient L2 learners who have the same L1.

Abstract

The endeavor to understand the human brain has seen more progress in the last few decades than in the previous two millennia. Still, our understanding of how the human brain relates to behavior in the real world and how this link is modulated by biological, social, and environmental factors is limited. To address this, we designed the Healthy Brain Study (HBS), an interdisciplinary, longitudinal, cohort study based on multidimensional, dynamic assessments in both the laboratory and the real world. Here, we describe the rationale and design of the currently ongoing HBS. The HBS is examining a population-based sample of 1,000 healthy participants (age 30-39) who are thoroughly studied across an entire year. Data are collected through cognitive, affective, behavioral, and physiological testing, neuroimaging, bio-sampling, questionnaires, ecological momentary assessment, and real-world assessments using wearable devices. These data will become an accessible resource for the scientific community enabling the next step in understanding the human brain and how it dynamically and individually operates in its bio-social context. An access procedure to the collected data and bio-samples is in place and published on https://www.healthybrainstudy.nl/en/data-and-methods.

https://www.trialregister.nl/trial/7955

Abstract

Using the visual-word paradigm, the present study investigated the effects of word onset and offset masking on the time course of non-native spoken-word recognition in the presence of background noise. In two experiments, Dutch non-native listeners heard English target words, preceded by carrier sentences that were noise-free (Experiment 1) or contained intermittent noise (Experiment 2). Target words were either onset- or offset-masked or not masked at all. Results showed that onset masking delayed target word recognition more than offset masking did, suggesting that – similar to natives – non-native listeners strongly rely on word onset information during word recognition in noise.

Abstract

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.

Abstract

One of the challenges in speech perception is that listeners must deal with considerable
segmental and suprasegmental variability in the acoustic signal due to differences between talkers. Most previous studies have focused on how listeners deal with segmental variability.
In this EEG experiment, we investigated whether listeners track talker-specific usage of suprasegmental cues to lexical stress to recognize spoken words correctly. In a three-day training phase, Dutch participants learned to map non-word minimal stress pairs onto different object referents (e.g., USklot meant “lamp”; usKLOT meant “train”). These non-words were
produced by two male talkers. Critically, each talker used only one suprasegmental cue to signal stress (e.g., Talker A used only F0 and Talker B only intensity). We expected participants to learn which talker used which cue to signal stress. In the test phase, participants indicated whether spoken sentences including these non-words were correct (“The word for lamp is…”).
We found that participants were slower to indicate that a stimulus was correct if the non-word was produced with the unexpected cue (e.g., Talker A using intensity). That is, if in training Talker A used F0 to signal stress, participants experienced a mismatch between predicted and perceived phonological word-forms if, at test, Talker A unexpectedly used intensity to cue
stress. In contrast, the N200 amplitude, an event-related potential related to phonological
prediction, was not modulated by the cue mismatch. Theoretical implications of these
contrasting results are discussed. The behavioral findings illustrate talker-specific prediction of prosodic cues, picked up through perceptual learning during training.

Abstract

First-language research suggests that new words, after initial episodic-memory encoding, are consolidated and hence become lexically integrated. We asked here if lexical consolidation, about word forms and meanings, occurs in a second language. Italian–English sequential bilinguals learned novel English-like words (e.g., apricon, taught to mean “stapler”). fMRI analyses failed to reveal a predicted shift, after consolidation time, from hippocampal to temporal neocortical activity. In a pause-detection task, responses to existing phonological competitors of learned words (e.g., apricot for apricon) were slowed down if the words had been learned two days earlier (i.e., after consolidation time) but not if they had been learned the same day. In a lexical-decision task, new words primed responses to semantically-related existing words (e.g., apricon-paper) whether the words were learned that day or two days earlier. Consolidation appears to support integration of words into the bilingual lexicon, possibly more rapidly for meanings than for forms.

Abstract

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.

Abstract

We investigated music and language processing in a group of early bilinguals who spoke a tone language and a non-tone language (Cantonese and Dutch). We assessed online speech-music processing interactions, that is, interactions that occur when speech and music are processed simultaneously in songs, with a speeded classification task. In this task, participants judged sung pseudowords either musically (based on the direction of the musical interval) or phonologically (based on the identity of the sung vowel). We also assessed longer-term effects of linguistic experience on musical ability, that is, the influence of extensive prior experience with language when processing music. These effects were assessed with a task in which participants had to learn to identify musical intervals and with four pitch-perception tasks. Our hypothesis was that due to their experience in two different languages using lexical versus intonational tone, the early Cantonese-Dutch bilinguals would outperform the Dutch control participants. In online processing, the Cantonese-Dutch bilinguals processed speech and music more holistically than controls. This effect seems to be driven by experience with a tone language, in which integration of segmental and pitch information is fundamental. Regarding longer-term effects of linguistic experience, we found no evidence for a bilingual advantage in either the music-interval learning task or the pitch-perception tasks. Together, these results suggest that being a Cantonese-Dutch bilingual does not have any measurable longer-term effects on pitch and music processing, but does have consequences for how speech and music are processed jointly.

Abstract

The complementary learning systems account of word learning states that novel words, like other types of memories, undergo an offline consolidation process during which they are gradually integrated into the neocortical memory network. A fundamental change in the neural representation of a novel word should therefore occur in the hours after learning. The present EEG study tested this hypothesis by investigating whether novel words learned before a 24-hr consolidation period elicited more word-like oscillatory responses than novel words learned immediately before testing. In line with previous studies indicating that theta synchronization reflects lexical access, unfamiliar novel words elicited lower power in the theta band (4–8 Hz) than existing words. Recently learned words still showed a marginally lower theta increase than existing words, but theta responses to novel words that had been acquired 24 hr earlier were indistinguishable from responses to existing words. Consistent with evidence that beta desynchronization (16–21 Hz) is related to lexical-semantic processing, we found that both unfamiliar and recently learned novel words elicited less beta desynchronization than existing words. In contrast, no difference was found between novel words learned 24 hr earlier and existing words. These data therefore suggest that an offline consolidation period enables novel words to acquire lexically integrated, word-like neural representations.

Abstract

This study aims to test a prediction of recent
theoretical frameworks in speech motor control: if speech production targets are specified in auditory
terms, people with better auditory acuity should have more precise speech targets.
To investigate this, we had participants perform speech perception and production tasks in a counterbalanced order. To assess speech perception acuity, we used an adaptive speech discrimination
task. To assess variability in speech production, participants performed a pseudo-word reading task; formant values were measured for each recording.
We predicted that speech production variability to correlate inversely with discrimination performance.
The results suggest that people do vary in their production and perceptual abilities, and that better discriminators have more distinctive vowel production targets, confirming our prediction. This
study highlights the importance of individual
differences in the study of speech motor control, and sheds light on speech production-perception interaction.

Abstract

Children who start formal education in a second language may experience slower vocabulary growth in that language and subsequently experience disadvantages in literacy acquisition. The current study asked whether lexical specificity training can stimulate bilingual children's phonological awareness, which is considered to be a precursor to literacy. Therefore, Dutch monolingual and Turkish-Dutch bilingual children were taught new Dutch words with only minimal acoustic-phonetic differences. As a result of this training, the monolingual and the bilingual children improved on phoneme blending, which can be seen as an early aspect of phonological awareness. During training, the bilingual children caught up with the monolingual children on words with phonological overlap between their first language Turkish and their second language Dutch. It is concluded that learning minimal pair words fosters phoneme awareness, in both first and second language preliterate children, and that for second language learners phonological overlap between the two languages positively affects training outcomes, likely due to linguistic transfer

Abstract

This study asks how users of British Sign Language (BSL) recognize individual signs in connected sign sequences. We examined whether this is achieved through modality-specific or modality-general segmentation procedures. A modality-specific feature of signed languages is that, during continuous signing, there are salient transitions between sign locations. We used the sign-spotting task to ask if and how BSL signers use these transitions in segmentation. A total of 96 real BSL signs were preceded by nonsense signs which were produced in either the target location or another location (with a small or large transition). Half of the transitions were within the same major body area (e.g., head) and half were across body areas (e.g., chest to hand). Deaf adult BSL users (a group of natives and early learners, and a group of late learners) spotted target signs best when there was a minimal transition and worst when there was a large transition. When location changes were present, both groups performed better when transitions were to a different body area than when they were within the same area. These findings suggest that transitions do not provide explicit sign-boundary cues in a modality-specific fashion. Instead, we argue that smaller transitions help recognition in a modality-general way by limiting lexical search to signs within location neighbourhoods, and that transitions across body areas also aid segmentation in a modality-general way, by providing a phonotactic cue to a sign boundary. We propose that sign segmentation is based on modality-general procedures which are core language-processing mechanisms

Abstract

In different tasks involving action perception, performance has been found to be facilitated
when the presented stimuli were produced by the participants themselves rather than by
another participant. These results suggest that the same mental representations are
accessed during both production and perception. However, with regard to spoken word perception,
evidence also suggests that listeners’ representations for speech reflect the input
from their surrounding linguistic community rather than their own idiosyncratic productions.
Furthermore, speech perception is heavily influenced by indexical cues that may lead listeners
to frame their interpretations of incoming speech signals with regard to speaker identity.
In order to determine whether word recognition evinces similar self-advantages as found in
action perception, it was necessary to eliminate indexical cues from the speech signal. We therefore asked participants to identify noise-vocoded versions of Dutch words that were based on either their own recordings or those of a statistically average speaker. The majority of participants were more accurate for the average speaker than for themselves, even after taking into account differences in intelligibility. These results suggest that the speech
representations accessed during perception of noise-vocoded speech are more reflective
of the input of the speech community, and hence that speech perception is not necessarily based on representations of one’s own speech.

Abstract

In three cross-modal priming experiments we asked whether adaptation to a foreign-accented speaker is automatic, and whether adaptation can be seen after a long delay between initial exposure and test. Dutch listeners were exposed to a Hebrew-accented Dutch speaker with two types of Dutch words: those that contained [ɪ] (globally accented words), and those in which the Dutch [i] was shortened to [ɪ] (specific accent marker words). Experiment 1, which served as a baseline, showed that native Dutch participants showed facilitatory priming for globally accented, but not specific accent, words. In experiment 2, participants performed a 3.5-minute phoneme monitoring task, and were tested on their comprehension of the accented speaker 24 hours later using the same cross-modal priming task as in experiment 1. During the phoneme monitoring task, listeners were asked to detect a consonant that was not strongly accented. In experiment 3, the delay between exposure and test was extended to 1 week. Listeners in experiments 2 and 3 showed facilitatory priming for both globally accented and specific accent marker words. Together, these results show that adaptation to a foreign-accented speaker can be rapid and automatic, and can be observed after a prolonged delay in testing.

Abstract

We investigated neural mechanisms that support voice recognition in a training paradigm with fMRI. The same listeners were trained on different weeks to categorize the mid-regions of voice-morph continua as an individual's voice. Stimuli implicitly defined a voice-acoustics space, and training explicitly defined a voice-identity space. The predefined centre of the voice category was shifted from the acoustic centre each week in opposite directions, so the same stimuli had different training histories on different tests. Cortical sensitivity to voice similarity appeared over different time-scales and at different representational stages. First, there were short-term adaptation effects: Increasing acoustic similarity to the directly preceding stimulus led to haemodynamic response reduction in the middle/posterior STS and in right ventrolateral prefrontal regions. Second, there were longer-term effects: Response reduction was found in the orbital/insular cortex for stimuli that were most versus least similar to the acoustic mean of all preceding stimuli, and, in the anterior temporal pole, the deep posterior STS and the amygdala, for stimuli that were most versus least similar to the trained voice-identity category mean. These findings are interpreted as effects of neural sharpening of long-term stored typical acoustic and category-internal values. The analyses also reveal anatomically separable voice representations: one in a voice-acoustics space and one in a voice-identity space. Voice-identity representations flexibly followed the trained identity shift, and listeners with a greater identity effect were more accurate at recognizing familiar voices. Voice recognition is thus supported by neural voice spaces that are organized around flexible ‘mean voice’ representations.

Abstract

The possible-word constraint (PWC; Norris, McQueen, Cutler, & Butterfield, 1997) has been proposed as a language-universal segmentation principle: Lexical candidates are disfavoured if the resulting segmentation of continuous speech leads to vowelless residues in the input—for example, single consonants. Three word-spotting experiments investigated segmentation in Slovak, a language with single-consonant words and fixed stress. In Experiment 1, Slovak listeners detected real words such as ruka “hand” embedded in prepositional-consonant contexts (e.g., /gruka/) faster than those in nonprepositional-consonant contexts (e.g., /truka/) and slowest in syllable contexts (e.g., /dugruka/). The second experiment controlled for effects of stress. Responses were still fastest in prepositional-consonant contexts, but were now slowest in nonprepositional-consonant contexts. In Experiment 3, the lexical and syllabic status of the contexts was manipulated. Responses were again slowest in nonprepositional-consonant contexts but equally fast in prepositional-consonant, prepositional-vowel, and nonprepositional-vowel contexts. These results suggest that Slovak listeners use fixed stress and the PWC to segment speech, but that single consonants that can be words have a special status in Slovak segmentation. Knowledge about what constitutes a phonologically acceptable word in a given language therefore determines whether vowelless stretches of speech are or are not treated as acceptable parts of the lexical parse.

Abstract

Signed languages are articulated through simultaneous upper-body movements and are seen; spoken languages are articulated through sequential vocal-tract movements and are heard. But word recognition in both language modalities entails segmentation of a continuous input into discrete lexical units. According to the Possible Word Constraint (PWC), listeners segment speech so as to avoid impossible words in the input. We argue here that the PWC is a modality-general principle. Deaf signers of British Sign Language (BSL) spotted real BSL signs embedded in nonsense-sign contexts more easily when the nonsense signs were possible BSL signs than when they were not. A control experiment showed that there were no articulatory differences between the different contexts. A second control experiment on segmentation in spoken Dutch strengthened the claim that the main BSL result likely reflects the operation of a lexical-viability constraint. It appears that signed and spoken languages, in spite of radical input differences, are segmented so as to leave no residues of the input that cannot be words.

Abstract

Japanese listeners detected Japanese words embedded at the end of nonsense sequences (e.g., kaba 'hippopotamus' in gyachikaba). When the final portion of the preceding context together with the initial portion of the word (e.g., here, the sequence chika) was compatible with many lexical competitors, recognition of the embedded word was more difficult than when such a sequence was compatible with few competitors. This clear effect of competition, established here for preceding context in Japanese, joins similar demonstrations, in other languages and for following contexts, to underline that the functional architecture of the human spoken-word recognition system is a universal one.

Abstract

For optimal word recognition listeners should use all relevant acoustic information as soon as it comes available. Using printed-word eye-tracking we investigated when during word processing Dutch listeners use suprasegmental lexical stress information to recognize words. Fixations on targets such as 'OCtopus' (capitals indicate stress) were more frequent than fixations on segmentally overlapping but differently stressed competitors ('okTOber') before segmental information could disambiguate the words. Furthermore, prior to segmental disambiguation, initially stressed words were stronger lexical competitors than non-initially stressed words. Listeners recognize words by immediately using all relevant information in the speech signal.

Abstract

Four cross-modal repetition priming experiments examined whether consonant duration in Italian provides listeners with information not only for segmental identification ("what" information: whether the consonant is a geminate or a singleton) but also for lexical segmentation (“where” information: whether the consonant is in word-initial or word-medial position). Italian participants made visual lexical decisions to words containing geminates or singletons, preceded by spoken primes (whole words or fragments) containing either geminates or singletons. There were effects of segmental identity (geminates primed geminate recognition; singletons primed singleton recognition), and effects of consonant position (regression analyses revealed graded effects of geminate duration only for geminates which can vary in position, and mixed-effect modeling revealed a positional effect for singletons only in low-frequency words). Durational information appeared to be more important for segmental identification than for lexical segmentation. These findings nevertheless indicate that the same kind of information can serve both "what" and "where" functions in speech comprehension, and that the perceptual processes underlying those functions are interdependent.

Abstract

In foreign-accented speech, listeners have to handle noticeable deviations from the standard pronunciation of a target language. Three cross-modal priming experiments investigated how short- and long-term experiences with a foreign accent influence word recognition by native listeners. In experiment 1, German-accented words were presented to Dutch listeners who had either extensive or limited prior experience with German-accented Dutch. Accented words either contained a diphthong substitution that deviated acoustically quite largely from the canonical form (huis [hys], "house", pronounced as [hoys]), or that deviated acoustically to a lesser extent (lijst [lst], "list", pronounced as [lst]). The mispronunciations never created lexical ambiguity in Dutch. While long-term experience facilitated word recognition for both types of substitutions, limited experience facilitated recognition only of words with acoustically smaller deviations. In experiment 2, Dutch listeners with limited experience listened to the German speaker for 4 min before participating in the cross-modal priming experiment. The results showed that speaker-specific learning effects for acoustically large deviations can be obtained already after a brief exposure, as long as the exposure contains evidence of the deviations. Experiment 3 investigates whether these short-term adaptation effects for foreign-accented speech are speaker-independent.