Period For Language Acquisition Research Articles

Statistical learning and the critical period: how a continuous learning mechanism can give rise to discontinuous learning.

Infants and children are generally more successful than adults in learning novel languages, a phenomenon referred to as a critical or sensitive period for language acquisition. One explanation for this critical period is the idea that children have access to a set of language learning processes or mechanisms unavailable to adults. From this perspective, developmental change is explained in terms of a discontinuity of learning processes. We suggest that this is not the only possible explanation for developmental change in language learning outcomes. Instead, we propose that the mechanisms underlying language acquisition (in particular, we highlight statistical learning) are largely continuous across the lifespan. From this perspective, developmental change is explained in terms of experience, differences in the input with age, and maturational changes in the cognitive architecture supporting learning, even while the learning process itself operates continuously across developmental time. WIREs Cogn Sci 2016, 7:276-288. doi: 10.1002/wcs.1394 For further resources related to this article, please visit the WIREs website.

JOURNAL OF PEDIATRIC CRITICAL CARE

The Landau-Kleffner syndrome or the syndrome of acquired epileptic aphasia was first described in 1957. The disorder is characterized by gradual or rapid loss of language in a previously normal child. Acquired epileptic aphasia (AEA) typically develops in healthy children who acutely or progressively lose receptive and expressive language ability coincident with the appearance of paroxysmal electroencephalographs (EEG) changes. In most cases described in detail, a clearly normal period of motor and language development occurs before acquired epileptic aphasia symptoms appear. Because this syndrome appears during such a critical period of language acquisition in a child’s life, speech production may be affected just as severely as language comprehension. The onset of LKS is typically between 18 months and 13 years. The prevalence of clinical seizures in acquired epileptic aphasia (LKS) is 70-85%. The syndrome can be difficult to diagnose and may be misdiagnosed as autism, pervasive developmental disorder, hearing impairment, learning disability, auditory/ verbal processing disorder, attention deficit disorder, intellectual disability, childhood schizophrenia, or emotional/behavioural problems. An EEG (electroencephalogram) test is imperative to a diagnosis.

Innate Immunity: Orchestrating Inflammation and Resolution of Otitis Media.

Otitis media (OM) is a common disease in young children, accounting for more office visits and surgeries than any other pediatric condition. It is associated with an estimated cost of five billion dollars annually in the USA. Moreover, chronic and recurrent middle ear (ME) disease leads to hearing loss during critical periods of language acquisition and learning leading to delays in reaching developmental milestones and risking permanent damage to the ME and inner ear in severe cases. Therefore, research to understand the disease pathogenesis and identify new therapeutics is important. Although OM is a multifactorial disease, targeting the molecular mechanisms that drive inflammation and OM resolution is critical. In this review, we discuss the current evidence suggesting that innate immune receptors and effectors play key roles in OM by mediating both the ME inflammatory responses and recovery.

The irreversibility of sensitive period effects in language development: evidence from second language acquisition in international adoptees.

The question of a sensitive period in language acquisition has been subject to extensive research and debate for more than half a century. While it has been well established that the ability to learn new languages declines in early years, the extent to which this outcome depends on biological maturation in contrast to previously acquired knowledge remains disputed. In the present study, we addressed this question by examining phonetic discriminatory abilities in early second language (L2) speakers of Swedish, who had either maintained their first language (L1) (immigrants) or had lost it (international adoptees), using native speaker controls. Through this design, we sought to disentangle the effects of the maturational state of the learner on L2 development from the effects of L1 interference: if additional language development is indeed constrained by an interfering L1, then adoptees should outperform immigrant speakers. The results of an auditory lexical decision task, in which fine vowel distinctions in Swedish had been modified, showed, however, no difference between the L2 groups. Instead, both L2 groups scored significantly lower than the native speaker group. The three groups did not differ in their ability to discriminate non-modified words. These findings demonstrate that L1 loss is not a crucial condition for successfully acquiring an L2, which in turn is taken as support for a maturational constraints view on L2 acquisition. A video abstract of this article can be viewed at: https://youtu.be/1J9X50aePeU.

Langage, cerveau et vieillissement : une complicité tout au long de la vie

The neurobiological bases of language remain activated long after the period of language acquisition. Growing evidence shows that the neurofunctional organization of language develops throughout one’s lifetime and thus contributes to the maintenance of communication abilities, an important element for active aging. However, the maintenance of communication abilities in older people is in contrast with the observed neurobiological changes taking place, therefore demonstrating that a paradox exists, known as the brain-cognition mismatch. It has been hypothesized that neurofunctional reorganization allows the brain to compensate for age-related neural decline and maintenance of various cognitive abilities, such as language. Several phenomena such as cognitive reserve, HAROLD, PASA, CRUNCH, and STAC have attempted to explain the mechanisms of cerebral reorganization. Yet no theory has fully explained this phenomenon yet, as the brain displays flexible strategies for adapting to aging. This review compares the semantic treatment of words—a language component usually well preserved during aging—between younger and older adults, while observing the characteristics of neurofunctional reorganization.

A Preliminary Study on Interpreting for Emergent Signers

Sign language interpreters work with a variety of consumer populations throughout their careers. One such population, referred to as emergent signers , consists of consumers who are in the process of learning American Sign Language, and who rely on interpreters during their language acquisition period. A gap in the research is revealed when considering the interaction between this growing population and the interpreting field. The present study thus attempts to provide a preliminary examination of the topic by reporting on the findings of a survey conducted with interpreters affiliated with Gallaudet Interpreting Service at Gallaudet University. Results show that interpreters are working on a regular basis with this population that the work is different from traditional interpreting work with fluent signers, and that interpreters have differing opinions on how the work should be approached. Implications for future areas of study and the overwhelming need for research on this subject are also discussed.

Neurodevelopmental Constraints of Syntax Rule Transfer Effects as Landmarks for Sensitive Periods of Language Acquisition

Mastering syntactic rules, which determine how words are combined into phrases, is crucial for understanding language. There is a longstanding debate in the literature concerning the formation of such rules. Some authors have argued that in adults the cognitive implementation of syntax is based on

Effects of early auditory deprivation on auditory-visual development

Auditory perception does not develop in isolation. In typically developing infants, the auditory system develops integrally with other sensory and motor systems. This integrality is disrupted in deaf infants. Even those who gain access to sound through cochlear implantation undergo a period of auditory deprivation where the other sensory systems develop independently from audition before access to sound begins. In this presentation, I will report findings from several studies of infants and toddlers with cochlear implants where we have found that they perform more poorly on auditory-visual integration and association tasks (e.g., novel word learning) than normal-hearing peers. Moreover, longer periods of auditory deprivation correlate with poorer performance on auditory-visual association tasks. I will discuss the implications of these findings on sensitive period of language acquisition. I will also present preliminary results from a new study that is further exploring multi-modal integration and learning in hearing-impaired infants. We are using head-mounted cameras, eye trackers, and microphones to analyze multi-modal communicative interactions between infants with hearing loss and their parents during free play sessions. By investigating the dynamics between multi-modal input and interactive behavior, we hope to gain important insights into how impaired sensory integration affects communicative interactions and multi-modal learning.

Effects of age of learning on voice onset time: categorical perception of Swedish stops by near-native L2 speakers.

This study examined the effects of age of onset (AO) of L2 acquisition on the categorical perception of the voicing contrast in Swedish word-initial stops varying in voice onset time (VOT). Three voicing continua created on the basis of natural Swedish word pairs with /p-b/, /t-d/, /k-/ in initial position were presented to 41 Spanish early (AO < 12) and late (AO > 12) near-native speakers of L2 Swedish. Fifteen native speakers of Swedish served as controls. Categorizations were influenced by AO and listener status as L1/L2 speaker, in that the late learners deviated the most from native-speaker perception. In addition, only a small minority of the late learners perceived the voicing contrast in a way comparable to native-speaker categorization, while most early L2 learners demonstrated nativelike categorization patterns. However, when the results were combined with the L2 learners' production of Swedish voiceless stops (Stölten, 2005; Stölten, Abrahamsson & Hyltenstam, in press), nativelike production and perception was never found among the late learners, while a majority of the early learners still exhibited nativelike production and perception. It is concluded that, despite their being perceived as mother-tongue speakers of Swedish by native listeners, the late learners do not, after detailed phonetic scrutiny, exhibit a fully nativelike command of Swedish VOT. Consequently, being near-native rather than nativelike speakers of their second language, these individuals do not constitute the evidence necessary to reject the hypothesis of one or several critical (or sensitive) periods for language acquisition.

Language Acquisition in Late Critical Period: A Case Report

Studies carried out to support the existence of a critical period for language acquisition have concentrated mainly on the case of being in total deprivation from language contact, and in particular deprivation from auditory input in the entire time span before puberty. While arguing for a useful distinction between early and late critical periods, we attempt to investigate the written language production of a profoundly deaf young woman, here referred to as Maryam, who has missed the early years, before her official education as a deaf person began at the age of 54 months. During the study, several texts that we asked her to write were analysed. In addition, we held a test in which she was required to set disordered sentences in the right order. The results of text analysis indicated that despite her ability to communicate through written Persian, a considerable number of syntactically and morphologically ill-formed structures were observed in the texts she produced. While confirming the idea that some aspects of language, such as syntax and morphology, are affected much more than semantics and vocabulary, the existence of these deficits seems to strengthen the importance of early years in acquiring a language.

Formal mismatches and functional advantage in syntactic change

This paper relies on the idea that syntactic change stems from linguistic factors that are different in nature and, consequently, trigger different results. Specifically, I distinguish the causes, processes and results related to two different kinds of syntactic change, a ‘formal’ type of change vs. a ‘functional’ one. The hypotheses pursued here are the following: (i) Mismatches between the formal features a learner has acquired and certain data she receives during the language acquisition period lead to a syntactic change type, which restructures completely the syntactic derivation involved; (ii) The advantage of parsing one variant over parsing another triggers a different kind of change, namely one that affects specific instances or uses / registers of the crucial syntactic structure. To illustrate this, I analyze the role of functional advantage and formal changes in the historical development of the case system of Russian non-verbal predication.

Sensitive periods for language and recovery from stroke: Conceptual and practical parallels

In this review, we consider the literature on sensitive periods for language acquisition from the perspective of the stroke recovery literature treated in this Special Issue. Conceptually, the two areas of study are linked in a number of ways. For example, the fact that learning itself can set the stage for future failures to learn (in second language learning) or to remediate (as described in constraint therapy) is an important insight in both areas, as is the increasing awareness that limits on learning can be overcome by creating the appropriate environmental context. Similar practical issues, such as distinguishing native-like language acquisition or recovery of function from compensatory mechanisms, arise in both areas as well.

Language development after cochlear implantation: an epigenetic model.

Growing evidence supports the notion that dynamic gene expression, subject to epigenetic control, organizes multiple influences to enable a child to learn to listen and to talk. Here, we review neurobiological and genetic influences on spoken language development in the context of results of a longitudinal trial of cochlear implantation of young children with severe to profound sensorineural hearing loss in the Childhood Development after Cochlear Implantation study. We specifically examine the results of cochlear implantation in participants who were congenitally deaf (N = 116). Prior to intervention, these participants were subject to naturally imposed constraints in sensory (acoustic–phonologic) inputs during critical phases of development when spoken language skills are typically achieved rapidly. Their candidacy for a cochlear implant was prompted by delays (n = 20) or an essential absence of spoken language acquisition (n = 96). Observations thus present an opportunity to evaluate the impact of factors that influence the emergence of spoken language, particularly in the context of hearing restoration in sensitive periods for language acquisition. Outcomes demonstrate considerable variation in spoken language learning, although significant advantages exist for the congenitally deaf children implanted prior to 18 months of age. While age at implantation carries high predictive value in forecasting performance on measures of spoken language, several factors show significant association, particularly those related to parent–child interactions. Importantly, the significance of environmental variables in their predictive value for language development varies with age at implantation. These observations are considered in the context of an epigenetic model in which dynamic genomic expression can modulate aspects of auditory learning, offering insights into factors that can influence a child’s acquisition of spoken language after cochlear implantation. Increased understanding of these interactions could lead to targeted interventions that interact with the epigenome to influence language outcomes with intervention, particularly in periods in which development is subject to time-sensitive experience.

Preventing complications in pediatric cochlear implantation

This review addresses four key areas of controversy in the prevention of common complications of pediatric cochlear implant surgery: reducing meningitis risk, managing acute otitis media (AOM) in the cochlear implant population, assessing the optimum age for implanting a child to take advantage of the critical periods of language acquisition, and managing the social risk in defining ethical issues still surrounding cochlear implant in children. Improved surgical techniques and the replacement of Prenvar-7 with Prenvar-13 significantly reduce the risk of cochlear implant related meningitis. AOM within 2 months of cochlear implant placement requires aggressive management to reduce the risk of complication. Tympanostomy tubes do not increase the risk of otitis media or meningitis and should be used when appropriate according to accepted AOM standards. Although the controversy over cochlear implant and the dissolution of Deaf Culture is decreasing, the use of cochlear implant in children remains an area for open dialogue between groups to ensure children are treated appropriately. Discussions ought to be based on fact and scientific evidence. Although cochlear implants remain the gold standard for hearing restoration in children with severe to profound hearing loss, several issues remain controversial and are in need of further scientific exploration.

The Comprehension and Production of Wh-Questions in Deaf and Hard-of-Hearing Children

Hearing loss during the critical period for language acquisition restricts spoken language input. This input limitation, in turn, may hamper syntactic development. This study examined the comprehension, production, and repetition of Wh-questions in deaf or hard-of-hearing (DHH) children. The participants were 11 orally trained Hebrew-speaking children aged 9.1-12.4 with moderate-to-profound hearing loss from birth, who consistently used hearing aids or cochlear implants and who had difficulties understanding relative clauses. Experiment 1 tested the comprehension of Wh-questions using a picture selection task, comparing subject with object questions and who- with which-questions; Experiment 2 tested the production of subject and object who-questions using an elicitation task; and Experiment 3 tested the repetition of Wh-questions and other structures derived by Wh-movement. All the DHH participants showed difficulty in the comprehension, production, and repetition of object questions, and their performance was significantly below that of hearing children. In contrast, they repeated embedded sentences without movement well, indicating that their deficit is in syntactic movement rather than embedding or the CP node in the syntactic tree. The results provide additional evidence that DHH children have difficulties with Wh-movement and emphasize that Wh-questions, which are crucial for communication, can be severely impaired in these children.

An exploratory study of linguistic–colour associations across languages in multilingual synaesthetes

In one of the most common forms of synaesthesia, linguistic-colour synaesthesia, colour is induced by stimuli such as numbers, letters, days of the week, and months of the year. It is not clear, however, whether linguistic-colour synaesthesia is determined more by higher level semantic information--that is, word meaning--or by lower level grapheme or phoneme structure. To explore this issue, we tested whether colour is consistently induced by grapheme or phoneme form or word meaning in bilingual and trilingual linguistic-colour synaesthetes. We reasoned that if the induced colour was related to word meaning, rather than to the acoustic or visual properties of the words, then the induced colours would remain consistent across languages. We found that colours were not consistently related to word meaning across languages. Instead, induced colours were more related to form properties of the word across languages, particularly visual structure. However, the type of inducing stimulus influenced specific colour associations. For example, colours to months of the year were more consistent across languages than were colours to numbers or days of the week. Furthermore, the effect of inducing stimuli was also associated with the age of acquisition of additional languages. Our findings are discussed with reference to a critical period in language acquisition on synaesthesia.

Age of Onset and Nativelikeness in a Second Language: Listener Perception Versus Linguistic Scrutiny

The incidence of nativelikeness in adult second language acquisition is a controversial issue in SLA research. Although some researchers claim that any learner, regardless of age of acquisition, can attain nativelike levels of second language (L2) proficiency, others hold that attainment of nativelike proficiency is, in principle, impossible. The discussion has traditionally been framed within the paradigm of a critical period for language acquisition and guided by the question of whether SLA is constrained by the maturation of the brain. The work presented in this article can be positioned among those studies that have focused exclusively on the apparent counterexamples to the critical period. We report on a large‐scale study of Spanish/Swedish bilinguals (n = 195) with differing ages of onset of acquisition (&lt;1–47 years), all of whom identify themselves as potentially nativelike in their L2. Listening sessions with native‐speaker judges showed that only a small minority of those bilinguals who had started their L2 acquisition after age 12, but a majority of those with an age of onset below this age, were actually perceived as native speakers of Swedish. However, when a subset (n = 41) of those participants who did pass for native speakers was scrutinized in linguistic detail with a battery of 10 highly complex, cognitively demanding tasks and detailed measurements of linguistic performance, representation, and processing, none of the late learners performed within the native‐speaker range; in fact, the results revealed also that only a few of the early learners exhibited actual nativelike competence and behavior on all measures of L2 proficiency that were employed. Our primary interpretation of the results is that nativelike ultimate attainment of a second language is, in principle, never attained by adult learners and, furthermore, is much less common among child learners than has previously been assumed.

Functional neuroimaging of speech perception during a pivotal period in language acquisition

A pivotal period in the development of language occurs in the second year of life, when language comprehension undergoes rapid acceleration. However, the brain bases of these advances remain speculative as there is currently no functional magnetic resonance imaging (fMRI) data from healthy, typically developing toddlers at this age. We investigated the neural basis of speech comprehension in this critical age period by measuring fMRI activity during passive speech comprehension in 10 toddlers (mean +/- SD; 21 +/- 4 mo) and 10 3-year-old children (39 +/- 3 mo) during natural sleep. During sleep, the children were presented passages of forward and backward speech in 20-second blocks separated by 20-second periods of no sound presentation. Toddlers produced significantly greater activation in frontal, occipital, and cerebellar regions than 3-year-old children in response to forward speech. Our results suggest that rapid language acquisition during the second year of life may require the utilization of frontal, cerebellar, and occipital regions in addition to classical superior temporal language areas. These findings are consistent with the interactive specialization hypothesis, which proposes that cognitive abilities develop from the interaction of brain regions that include and extend beyond those used in the adult brain.

Binaural interaction in specific language impairment: an auditory evoked potential study

The aim of the study was to examine whether auditory binaural interaction, defined as any difference between binaurally evoked responses and the sum of monaurally evoked responses, which is thought to index functions involved in the localization and detection of signals in background noise, is atypical in a group of children with specific language impairment (SLI). Binaural interaction components (BICs) in the brainstem were compared in 19 children with SLI (13 males, six females; age range 7y 4mo-11y 10mo; mean age 9y 7mo [SD 1y 2mo]), and 31 comparison children with typical language development (16 males, 15 females; age range 7y 1mo-11y 4mo; mean age 9y 7mo [SD 1y 5mo]). Children with SLI had a significantly smaller BIC amplitude than the comparison group. However, no clear relationship was found between BIC measures and severity of language impairment. We conclude that, for some children, SLI may be associated with reduced binaural interaction which may hinder the detection or localization of speech sounds from noisy contexts during critical periods of language acquisition.

Beyond the critical period: Processing-based explanations for poor grammaticality judgment performance by late second language learners

This research explores if poor grammaticality judgments of late (age of arrival ⩾ 12) second language learners often attributed to being beyond the critical period for language acquisition can be better explained by processing difficulties due to (1) low L2 working memory capacity, (2) poor L2 decoding, and/or (3) inadequate L2 processing speed. In Experiment 1, late L2 learners and native speakers performed measures of English working memory, decoding, and speed, and a grammaticality judgment task. Compared to native speakers, late L2 learners were poorer on all measures. L2 span, L2 decoding ability, and arrival age correlated with L2 judgment accuracy. Late L2 learners had less difficult judging some structures (e.g., word order, questions) than others (e.g., articles, regular past). To simulate these deficits, Experiment 2 placed native speakers under stressors relevant to memory (low or high digit load), decoding (noise), or speed (response deadline, compressed speech) during grammaticality judgment. Span and decoding scores correlated with judgment under relevant stressors. The stressors caused native speakers to show selective deficits in judgment, with some structures (e.g., word order) being less vulnerable to stress than others (e.g., regular past). Performance of natives under noise or memory stress paralleled that of late L2 learners, indicating a role for decoding and memory abilities in explaining poor grammaticality judgment.