Transcranial direct-current stimulation of core language areas facilitates novel word acquisition.

Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique that can alter the state of the stimulated brain area and thereby affect neurocognitive processes and resulting behavioural performance. Previous studies have shown disparate results with respect to tDCS effects on language function, particularly with respect to language learning and word acquisition. To fill this gap, this study aimed at systematically addressing the effects of tDCS of core left-hemispheric language cortices on the brain mechanisms underpinning two main neurocognitive strategies of word learning: implicit inference-based Fast Mapping (FM) and direct instruction-based Explicit Encoding (EE). Prior to a word-learning session, 160 healthy participants were given 15 min of either anodal or cathodal tDCS of Wernicke's or Broca's areas, or a control sham (placebo) stimulation, using a between-group design. Each participant then learned 16 novel words (8 through FM and 8 through EE) in a contextual word-picture association session. Moreover, these words were learnt either perceptually via auditory exposure combined with a graphical image of the novel object, or in an articulatory mode, where the participants additionally had to overtly articulate the novel items. These learning conditions were fully counterbalanced across participants, stimuli and tDCS groups. Learning outcomes were tested at both lexical and semantic levels using two tasks: recognition and word-picture matching. EE and FM conditions produced similar outcomes, indicating comparable efficiency of the respective learning strategies. At the same time, articulatory learning produced generally better results than non-articulatory exposure, yielding higher recognition accuracies and shorter latencies in both tasks. Crucially, real tDCS led to global outcome improvements, demonstrated by faster (compared to sham) reactions, as well as some accuracy changes. There was also evidence of more specific tDCS effects: better word-recognition accuracy for EE vs. FM following cathodal stimulation as well as more expressed improvements in recognition accuracy and reaction times for anodal Broca's and cathodal Wernicke's stimulation, particularly for unarticulated FM items. These learning mode-specific effects support the notion of partially distinct brain mechanisms underpinning these two learning strategies. Overall, numerically largest improvements were observed for anodal Broca's tDCS, whereas the least expressed benefits of tDCS for learning were measured after anodal Wernicke stimulation. Finally, we did not find any inhibitory effects of either tDCS polarity in any of the comparisons. We conclude that tDCS of core language areas exerts a general facilitatory effect on new word acquisition with some limited specificity to learning protocols - the result that may be of potential applied value for future research aimed at ameliorating learning deficits and language disorders.

How Infants Link Nonce Phrases to Scenes With Objects and Predicates.

When infants hear sentences containing unfamiliar words, are some language-world links (such as noun-object) more readily formed than others (verb-predicate)? We examined English learning 14-15-month-olds' capacity for linking referents in scenes with bisyllabic nonce utterances. Each of the two syllables referred either to the object's identity, or the object's motion. Infants heard the syllables in either a Verb-Subject (VS) or Subject-Verb (SV) order. Learning was tested using preferential looking. The results showed that infants learned the nouns and verbs equally well. In addition, in both the VS- and SV-consistent conditions, infants learned the meaning of the utterance-final syllable, but not the utterance-initial one. A follow-up experiment that manipulated the prosodic cues of the test phrases confirmed that infants had decomposed the bisyllabic phrases into two distinct word-units. Thus, any biases potentially favoring noun or verb learning played a smaller role than utterance position did when noun and verb learning were equally supported by context.

Of Mouses and Mans: A Test of Errorless Versus Error-Based Learning in Children.

For both adults and children, learning from one's mistakes (error-based learning) has been shown to be advantageous over avoiding errors altogether (errorless learning) in pedagogical settings. However, it remains unclear whether this advantage carries over to nonpedagogical settings in children, who mostly learn language in such settings. Using irregular plurals (e.g., "mice") as a test case, we conducted a corpus analysis (N = 227) and two preregistered experiments (N = 56, N = 99), to investigate the potency of error-based learning as a mechanism for language acquisition in 3- and 4-year-old children. The results of the corpus analysis showed that incidental feedback after errors, in the form of caregivers' reformulations of children's errors, was relatively infrequent, had modest informational value, and was rarely used by children to correct their errors immediately. The following two experiments contrasted error-based learning with errorless learning, where the correct utterance was modeled for the child before a potential error was committed. The results showed that error-based learning was not always effective, and when it was, it was certainly not superior to errorless learning. Collectively, these findings question the extension of the benefits of error-based learning from pedagogical to nonpedagogical settings and define constraints under which one mechanism may be more beneficial to learning than the other.

Chinese Folk Songs Can Facilitate Chinese Language Learning - A Pilot Study.

While previous research has demonstrated the beneficial role of pop music in foreign language learning, there is a lack of studies exploring the potential impact of Chinese folk songs on Mandarin language acquisition. This study aimed to investigate whether a curriculum based on Chinese folk songs enhances the outcomes of Mandarin Chinese learning in foreign speakers. International students in a university in Beijing who were attending regular Mandarin courses were allocated into two groups: the group receiving an additional Chinese folk song-based curriculum (intervention) and the group not (control). Mandarin proficiency after one and two semesters between the two groups was assessed using the Chinese Proficiency Test (i.e., Hanyu Shuiping Kaoshi, HSK) by the Generalized Estimating Equations (GEE) analyses. 16 international students were analysed (intervention: 8; control: 8). After adjusting for time, the intervention group showed a significantly higher HSK score in listening section (adjusted ß = 7.86, p = 0.015) than that of the control group. In conclusions, Chinese folk song-based curriculum has the potential to enhance Mandarin listening among foreign speakers.

The effects of phonological and semantic similarity on early referent identification.

Language processing encompasses a sophisticated interplay of phonological (sound-based) and semantic (meaning-based) processes. This intricate interaction develops progressively during early language acquisition. It involves not only the addition of new words to the child's vocabulary but also the evolving organization of lexico-semantic networks. The aim of the current research was to investigate how young children navigate the complexities of word relationships, with a focus on the interplay between phonological similarity and semantic relatedness. A preferential looking experiment was conducted involving 73 participants divided into two age groups, with 39 aged 18 months and 34 aged 24 months. The experimental design involved auditory presentation of target words together with pairs of target and distractor images that systematically varied the phonological and semantic similarity between the pairs. The results showed a significant developmental progression in young children's phonological and semantic processing abilities. At 18 months, children predominantly responded to phonological cues, displaying challenges in distinguishing between phonologically similar words regardless of semantic context. By 24 months, there was an evident sensitivity to both phonological and semantic cues. This age group especially showed processing difficulties with words that were both phonologically similar and semantically related, suggesting a more complex integration of lexico-semantic networks. These findings underscore the pivotal role of phonological processing in early language acquisition and point to the gradual integration of semantic relationships into children's lexicons.

Leader-follower dynamics during early social interactions matter for infant word learning.

We know little about the mechanisms through which leader-follower dynamics during dyadic play shape infants' language acquisition. We hypothesized that infants' decisions to visually explore a specific object signal focal increases in endogenous attention, and that when caregivers respond to these proactive behaviors by naming the object it boosts infants' word learning. To examine this, we invited caregivers and their 14-mo-old infants to play with novel objects, before testing infants' retention of the novel object-label mappings. Meanwhile, their electroencephalograms were recorded. Results showed that infants' proactive looks toward an object during play associated with greater neural signatures of endogenous attention. Furthermore, when caregivers named objects during these episodes, infants showed greater word learning, but only when caregivers also joined their focus of attention. Our findings support the idea that infants' proactive visual explorations guide their acquisition of a lexicon.

Effects of semantic and pragmatic factors on preschool children's negation-triggered inferences on plausible alternatives.

Negation-triggered inferences are universal across human languages. Hearing "This is not X" should logically lead to the inference that all elements other than X constitute possible alternatives. However, not all logically possible alternatives are equally accessible in the real world. To qualify as a plausible alternative, it must share with the negated element as many similarities as possible, and the most plausible one is often from the same taxonomic category as the negated element. The current article reports on two experiments that investigated the development of preschool children's ability to infer plausible alternatives triggered by negation. Experiment 1 showed that in a context where children were required to determine the most plausible alternative to the negated element, the 4- and 5-year-olds, but not the 3-year-olds, exhibited a robust preference for the taxonomic associates. Experiment 2 further demonstrated that the 3-, 4- and 5-year-olds considered all the complement set members as equally possible alternatives in a context where they were not explicitly required to evaluate the plausibility of different candidates. Taken together, our findings reveal interesting developmental continuity in preschool children's ability to make inferences about plausible alternatives triggered by negation. We discuss the potential semantic and pragmatic factors that contribute to children's emerging awareness of typical alternatives triggered by negative expressions.

Zipfian distributions facilitate children's learning of novel word-referent mappings.

The word-frequency distributions children hear during language learning are highly skewed (Zipfian). Previous studies suggest that such skewed environments confer a learnability advantage in tasks that require the learner to discover the units that have to be learned, as in word-segmentation or cross-situational learning. This facilitative effect has been attributed to contextual facilitation from high frequency items in learning lower frequency items, and to better learning under the increased predictability (lower entropy) of skewed distributions. Here, we ask whether Zipfian distributions facilitate learning beyond the discovery of units, as expected under the predictability account. We tested children's learning of novel word-referent mappings in a learning task where each mapping was presented in isolation during training, and did not need to be dicovered. We compared learning in a uniform environment to two skewed environments with different entropy levels. Children's learning was overall better in the two skewed environments, even for low frequency items. These results extend the facilitative effect of Zipfian distributions to additional learning tasks and show they can facilitate language learning beyond the discovery of units.

Enhancing lexical tone learning for second language speakers: effects of acoustic properties in Mandarin tone perception.

Understanding the challenges faced by second language (L2) learners in lexical tone perception is crucial for effective language acquisition. This study investigates the impact of exaggerated acoustic properties on facilitating Mandarin tone learning for English speakers. Using synthesized tone stimuli, we systematically manipulated pitch contours through three key modifications: expanding the fundamental frequency (F0), increasing F0 (female voice), and extending the overall duration. Our objectives were to assess the influence of F0 expansion, higher F0, longer duration, and varied syllables on Mandarin tone learning and generalization. Participants engaged in a non-adaptive trial-by-trial tone identification task. Mixed-effects logistic regression modeling was used to analyze accuracy across learning phases, acoustic factors, and tones. Findings reveal improvements in accuracy from training to testing and generalization phases, indicating the effectiveness of perceptual training to tone perception for adult English speakers. Tone 1 emerged as the easiest to perceive, while Tone 3 posed the most challenge, consistent with established hierarchies of tonal acquisition difficulty. Analysis of acoustic factors highlighted tone-specific effects. Expanded F0 was beneficial for the identification of Tone 2 and Tone 3 but posed challenges for Tone 1 and Tone 4. Additionally, longer durations also exhibited varied effects across tones, aiding in the identification of Tone 3 and Tone 4 but hindering Tone 1 identification. The higher F0 was advantageous for Tone 2 but disadvantageous for Tone 3. Furthermore, the syllable ma facilitated the identification of Tone 1 and Tone 2 but not for Tone 3 and Tone 4. These findings enhance our understanding of the role of acoustic properties in L2 tone perception and have implications for the design of effective training programs for second language acquisition.

The Limitations of Large Language Models for Understanding Human Language and Cognition.

Researchers have recently argued that the capabilities of Large Language Models (LLMs) can provide new insights into longstanding debates about the role of learning and/or innateness in the development and evolution of human language. Here, we argue on two grounds that LLMs alone tell us very little about human language and cognition in terms of acquisition and evolution. First, any similarities between human language and the output of LLMs are purely functional. Borrowing the "four questions" framework from ethology, we argue that what LLMs do is superficially similar, but how they do it is not. In contrast to the rich multimodal data humans leverage in interactive language learning, LLMs rely on immersive exposure to vastly greater quantities of unimodal text data, with recent multimodal efforts built upon mappings between images and text. Second, turning to functional similarities between human language and LLM output, we show that human linguistic behavior is much broader. LLMs were designed to imitate the very specific behavior of human writing; while they do this impressively, the underlying mechanisms of these models limit their capacities for meaning and naturalistic interaction, and their potential for dealing with the diversity in human language. We conclude by emphasising that LLMs are not theories of language, but tools that may be used to study language, and that can only be effectively applied with specific hypotheses to motivate research.

Longitudinal trajectories of the neural encoding mechanisms of speech-sound features during the first year of life.

Infants quickly recognize the sounds of their mother language, perceiving the spectrotemporal acoustic features of speech. However, the underlying neural machinery remains unclear. We used an auditory evoked potential termed frequency-following response (FFR) to unravel the neural encoding maturation for two speech sound characteristics: voice pitch and temporal fine structure. 37 healthy-term neonates were tested at birth and retested at the ages of six and twelve months. Results revealed a reduction in neural phase-locking onset to the stimulus envelope from birth to six months, stabilizing by twelve months. While neural encoding of voice pitch remained consistent across ages, temporal fine structure encoding matured rapidly from birth to six months, without further improvement from six to twelve months. Results highlight the critical importance of the first six months of life in the maturation of neural encoding mechanisms that are crucial for phoneme discrimination during early language acquisition.

Continuing the conversation about echolalia and gestalt language development: A response to Haydock, Harrison, Baldwin, and Leadbitter.

LAY ABSTRACT: It was recently suggested that a set of ideas known as gestalt language development be embraced as a neurodiversity-affirmative practice. Neurodiversity refers to the idea that people interact with the world in many different ways and that there is not a single right way to do so. Some aspects of gestalt language development, such as embracing autistic communication, are consistent with neurodiversity. However, gestalt language development is also associated with numerous ideas, assertions, and clinical strategies that lack theoretical and empirical support. For this reason, we believe it is premature to embrace gestalt language development as a neurodiversity-affirmative practice. We propose that it is important to make sure we use language that differentiates between delayed echolalia and the broader set of ideas that comprise gestalt language development. We also suggest that it is important to discuss the relationship between neurodiversity-affirmative practices and practices supported by research evidence.

The use of formal language as a strong sign of verbal autistic children in diglossic communities: The case of Arabic.

The current study aimed to investigate whether the use of formal language (Modern Standard Arabic [MSA]) by young children in diglossic Arab communities offers diagnostic insights, especially for verbal autistic children and to further explore this phenomenon. We used a cohort study design, with 4-6-year-old fluent first language Arabic-speaking children attending Arabic Kindergartens in two representative Kuwait governates. Reported cases for MSA use were assessed via a computer-based structured language test and corroborated cases were further assessed for exposure to sources of MSA, verbal IQ, temperamental characteristics, and autism spectrum disorder (ASD). Four children from the same class without developmental difficulties were selected for each MSA user as control group. The frequency of MSA use among verbal pre-schoolers was 0.46%. Use of MSA did not correlate with parents' education, amount of exposure to MSA, verbal IQ, but with severity of ASD. Predicted probability of ASD in the presence of MSA was 0.86. Executive functions of ASD-MSA users were similar to those of the control group and significantly higher than unselected autistic peers in the literature. The use of MSA has the potential to serve as a strong sign for the diagnosis of verbal autistic children, often missed or delayed in being diagnosed. We also discuss strategies via which language is acquired in ASD.

Neural Mechanisms of Learning and Consolidation of Morphologically Derived Words in a Novel Language: Evidence From Hebrew Speakers.

We examined neural mechanisms associated with the learning of novel morphologically derived words in native Hebrew speakers within the Complementary Learning Systems (CLS) framework. Across four sessions, 28 participants were trained on an artificial language, which included two types of morphologically complex words: linear (root + suffix) with a salient structure, and non-linear (root interleaved with template), with a prominent derivational structure in participants' first language (L1). A third simple monomorphemic condition, which served as baseline, was also included. On the first and fourth sessions, training was followed by testing in an fMRI scanner. Our behavioural results showed decomposition of both types of complex words, with the linear structure more easily learned than the non-linear structure. Our fMRI results showed involvement of frontal areas, associated with decomposition, only for the non-linear condition, after just the first session. We also observed training-related increases in activation in temporal areas specifically for the non-linear condition, which was correlated with participants' L1 morphological awareness. These results demonstrate that morphological decomposition of derived words occurs in the very early stages of word learning, is influenced by L1 experience, and can facilitate word learning. However, in contrast to the CLS framework, we found no support for a shift from reliance on hippocampus to reliance on cortical areas in any of our conditions. Instead, our findings align more closely with recent theories showing a positive correlation between changes in hippocampus and cortical areas, suggesting that these representations co-exist and continue to interact with one another beyond initial learning.

Developing, validating, and piloting a MultiTeachViews questionnaire on L1 and translation use: Attitudes of Kazakhstani secondary school EFL teachers.

This study developed, validated, and piloted a MultiTeachViews questionnaire to investigate secondary school English as a Foreign Language (EFL) teachers' attitudes towards multilingual teaching practices such as L1 and translation use. Initially, a literature review and focus group interview with six in-service EFL teachers were conducted to capture prevailing attitudes and inform content areas for the questionnaire. Items were then crafted, followed by the adoption of a 5-point Likert scale. Validation involved assessing internal and content validity through a structured checklist and expert evaluation. The pilot phase included think-aloud protocols with two teachers and a reliability test across a broader cohort of 100 teachers. Reliability testing yielded satisfactory Cronbach's Alpha coefficients (α > .70) for all scales, affirming the instrument's internal consistency. Consequently, the instrument is found to be a reliable and valid measure of EFL teachers' attitudes towards L1 and translation use in the classroom, with significant implications for Applied Linguistic and Second Language Acquisition research.•Developed, validated, and piloted a MultiTeachViews questionnaire for investigating attitudes.•Employed mixed methods in the development, validation, and piloting phases.•Found MultiTeachViews to be a reliable and valid measure of EFL teachers' attitudes towards multilingual teaching practices, such as L1 and translation use.

Adults Adapt to Child Speech in Causative Semantics.

Causation is a core feature of human cognition and language. How children learn about intricate causal meanings is yet unresolved. Here, we focus on how children learn verbs that express causation. Such verbs, known as lexical causatives (e.g., break and raise), lack explicit morphosyntactic markers indicating causation, thus requiring that the child generalizes the causal meaning from the context. The language addressed to children presumably plays a crucial role in this learning process. Hence, we tested whether adults adapt their use of lexical causatives to children when talking to them in day-to-day interactions. We analyzed naturalistic longitudinal data from 12 children in the Manchester corpus (spanning from 20 to 36 months of age). To detect semantic generalization, we employed a network approach with semantics learned from cross-situational contexts. Our results show an increasing trend in the expansion of causative semantics, observable in both child speech and child-directed speech. Adults consistently maintain somewhat more intricate causative semantic networks compared to children. However, both groups display evolving patterns. Around 28-30 months of age, children undergo a reduction in the degree of causative generalization, followed by a slightly time-lagged adjustment by adults in their speech directed to children. These findings substantiate adults' adaptation in child-directed speech, extending to semantics. They highlight child-directed speech as a highly adaptive and subconscious teaching tool that facilitates the dynamic processes of language acquisition.

Cognitive Fluency in L2: The Effect of Automatic and Controlled Lexical Processing on Speech Rate.

The fluency of second language (L2) speech can be influenced by L2 proficiency, but also by differences in the efficiency of cognitive operations and personal speaking styles. The nature of cognitive fluency is still, however, little understood. Therefore, we studied the cognitive fluency of Finnish advanced students of English (N = 64) to understand how the efficiency of cognitive processing influences speech rate. Cognitive fluency was operationalised as automaticity of lexical access (measured by rapid word recognition) and attention control (measured by the Stroop task). The tasks were conducted in both L1 (Finnish) and L2 (English) to examine the (dis)similarity of processing in the two languages. Speech rate in a monologue task was used as the dependent measure of speaking performance. The results showed that after controlling for the L1 speech rate and L1 cognitive fluency, the L2 attention control measures explained a small amount of additional variance in L2 speech rate. These results are discussed in relation to the cognitive fluency framework and general speaking proficiency research.

Enhanced pitch discrimination in autistic children with unexpected bilingualism.

Some autistic children acquire foreign languages from exposure to screens. Such unexpected bilingualism (UB) is therefore not driven by social interaction, rather, language acquisition appears to rely on less socially mediated learning and other cognitive processes. We hypothesize that UB children may rely on other cues, such as acoustic cues, of the linguistic input. Previous research indicates enhanced pitch processing in some autistic children, often associated with language delays and difficulties in forming stable phonological categories due to sensitivity to subtle linguistic variations. We propose that repetitive screen-based input simplifies linguistic complexity, allowing focus on individual cues. This study hypothesizes that autistic UB children exhibit superior pitch discrimination compared with both autistic and non-autistic peers. From a sample of 46 autistic French-speaking children aged 9 to 16, 12 were considered as UB. These children, along with 45 non-autistic children, participated in a two-alternative forced-choice pitch discrimination task. They listened to pairs of pure tones, 50% of which differed by 3% (easy), 2% (medium), or 1% (hard). A stringent comparison of performance revealed that only the autistic UB group performed above chance for tone pairs that differed, across all conditions. This group demonstrated superior pitch discrimination relative to autistic and non-autistic peers. This study establishes the phenomenon of UB in autism and provides evidence for enhanced pitch discrimination in this group. Acute perception of auditory information, combined with repeated language content, may facilitate UB children's focus on phonetic features, and help acquire a language with no communicative support or motivation.

Beyond age: exploring ultimate attainment in heritage speakers and late L2 learners.

According to the Critical Period Hypothesis, successful language learning is optimal during early childhood, whereas language learning outside of this time window is unsuccessful. In this respect, early language acquisition is viewed as convergent and reliable but late acquisition is not. The present study revisits the idea of a critical period by investigating the grammatical attainment of early bilinguals/heritage speakers (HSs), late second/foreign language (L2) learners, and comparable groups of monolinguals by testing Greek-English bilinguals in the two languages they speak by means of a grammaticality judgment task. Our findings show that in English, HSs performed on par with monolinguals, both groups surpassing the late L2 learners, who performed about 2 SDs below the HSs and the monolinguals. In Greek, late L2 learners and monolinguals exhibited comparable performance, contrasting sharply with the HSs' significantly lower proficiency, which was on average about 5 SDs below the late L2 learners and the monolinguals. Consequently, our results show that the performance gaps between HSs and Greek monolinguals/late L2 learners were more pronounced than the differences between late L2 learners and English monolinguals/HSs, suggesting that the early bilinguals' success in English may come at the expense of their heritage language (Greek). Furthermore, we observe substantially more individual variation within HSs in their heritage language than within the late L2 learners for their second language. Thus, testing bilinguals in both of their languages allows us to unveil the complexity of grammatical ultimate attainment and prompt a re-thinking of age as the major determining factor of (un)successful attainment.