Language and memory abilities of internationally adopted children from China: evidence for early age effects

Delayed auditory experience results in past tense production difficulties and working memory deficits in children with cochlear implants: A comparison with children with developmental language disorder

Extent evidence has shown that morphosyntax is one of the most challenging linguistic areas for children with atypical early language experiences. Over the last couple of years, comparisons between deaf children with CIs and children with DLD have gained interest - as cases of atypical early language experiences, including, but not restricted to, delayed onset of exposure to language input and language-processing difficulties. Evidence suggests that the morphosyntactic difficulties experienced by deaf children with CIs and children with DLD are very similar in nature. However, the few studies that have directly compared both groups are inconclusive, with deaf children with CIs either performing significantly better or on par with children with DLD. These differences in findings can be attributed, in part at least, to a failure to implement essential methodological controls - even more so given that deaf children with CIs comprise a very diverse population. The goal of the present study was to directly compare the performance of deaf children with CIs to that of children with DLD on a morphosyntactic ability known to be particularly difficult for both groups. Specifically, the present study conducted a detailed examination of the past tense marking abilities of deaf children with CIs and children with DLD while controlling for factors specific to deaf children with CIs, for children's basic cognitive abilities as well as for children's age, sex assigned at birth, and SES. Past tense verbs are particularly relevant as they are used as a marker of developmental language disorder (DLD) in children learning French. Moreover, extent evidence shows that deaf children with CIs and children with DLD have important WM difficulties, but also that there is an association between auditory perception, processing abilities, and working memory (WM) abilities as well as with the acquisition of morphological features, including tense marking. Unfortunately, no study has examined the relation between the accurate production of past tense verbs and WM abilities in children with CIs and children with DLD learning French. Fifteen deaf children with CIs between 5 and 7 years of age were compared to 15 children with DLD and to 15 typically-developing monolingual controls (MON), matched on important variables, using a past tense elicitation task as well as measures of phonological and nonverbal WM abilities. The results confirm that the deaf children with CIs and the children with DLD both performed significantly lower than the MON controls on the past tense elicitation task - suggesting that difficulties with past tense verbs in French might not only be a marker of DLD but, instead, a correlate of atypical language acquisition. Of importance, the present study is the first to show that deaf children with CIs perform significantly lower than children with DLD on a past tense elicitation task - highlighting the importance of using methodological controls. As well, significant correlations were found between the performance of the deaf children with CIs and of the children with DLD on the past tense elicitation task and their phonological and nonverbal WM abilities. Taken together with previous studies conducted in the same populations, this represents another evidence suggesting that early atypical language experiences result in language and WM deficits, including morphosyntactic difficulties.

Exposure to sign language prior and after cochlear implantation increases language and cognitive skills in deaf children

Recent evidence suggests that deaf children with CIs exposed to nonnative sign language from hearing parents can attain age-appropriate vocabularies in both sign and spoken language. It remains to be explored whether deaf children with CIs who are exposed to early nonnative sign language, but only up to implantation, also benefit from this input and whether these benefits also extend to memory abilities, which are strongly linked to language development. The present study examined the impact of deaf children's early short-term exposure to nonnative sign input on their spoken language and their phonological memory abilities. Deaf children who had been exposed to nonnative sign input before and after cochlear implantation were compared to deaf children who never had any exposure to sign input as well as to children with typical hearing. The children were between 5;1 and 7;1 years of age at the time of testing and were matched on age, sex, and socioeconomic status. The results suggest that even short-term exposure to nonnative sign input has positive effects on general language and phonological memory abilities as well as on nonverbal working memory-with total length of exposure to sign input being the best predictor of deaf children's performance on these measures. The present data suggest that even access to early short-term nonnative visual language input is beneficial for the language and phonological memory abilities of deaf children with cochlear implants, suggesting also that parents should not be discouraged from learning and exposing their child to sign language. RESEARCH HIGHLIGHTS: This is the first study to examine the effects of early short-term exposure to nonnative sign input on French-speaking children with cochlear implants' spoken language and memory abilities. Early short-term nonnative exposure to sign input can have positive consequences for the language and phonological memory abilities of deaf children with CIs. Extended exposure to sign input has some additional and important benefits, allowing children to perform on par with children with typical hearing.

What risk factors for Developmental Language Disorder can tell us about the neurobiological mechanisms of language development

Language is a complex multidimensional cognitive system that is connected to many neurocognitive capacities. The development of language is therefore strongly intertwined with the development of these capacities and their neurobiological substrates. Consequently, language problems, for example those of children with Developmental Language Disorder (DLD), are explained by a variety of etiological pathways and each of these pathways will be associated with specific risk factors. In this review, we attempt to link previously described factors that may interfere with language development to putative underlying neurobiological mechanisms of language development, hoping to uncover openings for future therapeutical approaches or interventions that can help children to optimally develop their language skills.

The impact of early auditory experience for the acquisition of morphosyntactic abilities and working memory

Difficulty in acquiring object clitics (OCs), and the omission of OCs more specifically, is used as a marker of developmental language disorder (DLD) in children learning French. Research also suggests that OCs are a complex morphosyntactic property of French and, as such, they could be particularly taxing for working memory (WM) resources. In light of previous research, it seems more likely that difficulties with OCs could be a marker for atypical early language acquisition. Children receiving a cochlear implant (CI) represent a case of delayed language exposure linked to a lack of early auditory exposure. Few studies have investigated the production of clitics in children with CIs. Studies suggest that children with CIs make significantly more clitic omissions on tasks of clitic production than typically-developing (TD) children. To our knowledge, no study has looked at clitic comprehension in children with CIs learning French or at the relationship between WM and performance on tasks of OCs in this population. The present study aimed at examining the production and comprehension of OCs, as well as the relationship between clitic omission and WM, in both typically-developing monolinguals children and CI recipients learning French. Children with CIs performed significantly lower than the control group on both comprehension and production tasks. Clitic omission was significantly related to WM, but only in the CI group suggesting a differential relationship between early auditory experience, WM, and language acquisition.

Oral and Written Language Abilities of School-Age Internationally Adopted Children from Eastern Europe

PURPOSE

Children adopted from Eastern Europe were assessed at ages 6 to 7 years and results were compared to the same children when they were 8 years. Patterns of relative strengths and weaknesses in language, verbal memory and literacy were analyzed. Variables that predicted reading and writing were determined.

METHOD

Children adopted from Eastern Europe between 1;0 and 4;11 years of age were assessed at ages 6 to 7 years and age 8 years on a variety of tests that measured language, verbal memory and literacy. Results were compared across ages, and language, verbal memory and literacy domains.

RESULTS

Group means for all measures fell within the average range at both ages. The children's scores were not significantly different from test norms except for measures of rapid naming and number repetition. However, a larger than expected percentage of children scored -1SD below the mean on decontextualized measures of verbal working memory and reading fluency. At age 8 years 24% of children received speech language therapy services and 26% had repeated a grade level. Vocabulary, expressive syntax, verbal short-term memory and writing were areas of relative strength. Higher level vocabulary knowledge was strongly correlated with all literacy measures.

CONCLUSION

As a group, Eastern European adoptees scored average on measures of language and literacy at 6 or 7 years and again at age 8 years. However, 26% of the children had repeated a grade and 24% were still receiving speech and language services. Vocabulary was an area of strength reflecting the children's enriched adopted home environments. In-depth knowledge of vocabulary was the best predictor of reading and writing. Some aspects of working memory were a strength but others were not. Rapid naming was also a weakness.

The development of phonological memory and language: A multiple groups approach

Pierce et al. (2017) have proposed that variations in the timing, quality and quantity of language input during the earliest stages of development are related to variations in the development of phonological working memory and, in turn, to later language learning outcomes. To examine this hypothesis, three groups of children who are at-risk for language learning were examined: children with cochlear implants (CI), children with developmental language disorder (DLD), and internationally-adopted (IA) children, Comparison groups of typically-developing monolingual (MON) children and second language (L2) learners were also included. All groups were acquiring French as a first or second language and were matched on age, gender, and socioeconomic status, as well as other group-specific factors; they were between 5;0-7;3 years of age at time of testing. The CI and DLD groups scored significantly more poorly on the memory measures than the other groups; while the IA and L2 groups did not differ from one another. While the IA group performed more poorly than the MON group, there was no difference between the L2 and MON groups. We also found differential developmental relationships between phonological memory and language among the groups of interest in comparison to the typically-developing MON and L2 groups supporting the hypothesis that language experiences early in life are consequential for language development because of their effects on the development of phonological memory.

Internationally adopted children with and without a cleft lip and palate showed no differences in language ability at school-age

AIM

The aim of this study was to investigate language ability in internationally adopted children aged 7-8 years with and without a unilateral cleft lip and palate.

METHODS

We compared 27 internationally adopted children with a unilateral cleft lip and palate, adopted from China, with a group of 29 children without a cleft lip and palate, adopted from different countries. Participants were recruited from two cleft lip and palate teams in Sweden and through adoption organisations. Assessments were performed using standardised tests of speech and of receptive and expressive language ability. In addition, a parental questionnaire in which speech, language and communication aspects were rated was used.

RESULTS

There were no significant differences in language ability between the groups. The only difference was related to speech ability, where the internationally adopted children with unilateral cleft lip and palate scored significantly lower. However, a high proportion of children in both groups scored low on measures of expressive language compared with test norms.

CONCLUSION

The results suggested that having a cleft lip and palate did not increase the risk of language difficulties. Instead, being internationally adopted may be associated with a risk of delayed language development lasting for several years post-adoption.

A multi-group approach to examining language development in at-risk learners

A battery of standardized language tests and control measures was administered to three groups of at-risk language learners - internationally adopted children, deaf children with cochlear implants, and children with specific language impairment - and to groups of second-language learners and typically developing monolingual children. All children were acquiring French, were matched on age, gender, and socioeconomic status, and were between age 5;0 and 7;3 at the time of testing. Differences between the at-risk and not-at-risk groups were evident in all domains of language testing. The children with SLI or CIs scored significantly lower than the IA children and all three at-risk groups scored lower than the monolingual group; the L2 and IA groups scored similarly. The results suggest that children with limited access to, or ability to process, early language input are at greater risk than children with delayed input to an additional language but otherwise typical or relatively typical early input.

Past experience shapes ongoing neural patterns for language

Early experiences may establish a foundation for later learning, however, influences of early language experience on later neural processing are unknown. We investigated whether maintenance of neural templates from early language experience influences subsequent language processing. Using fMRI, we scanned the following three groups performing a French phonological working memory (PWM) task: (1) monolingual French children; (2) children adopted from China before age 3 who discontinued Chinese and spoke only French; (3) Chinese-speaking children who learned French as a second language but maintained Chinese. Although all groups perform this task equally well, brain activation differs. French monolinguals activate typical PWM brain regions, while both Chinese-exposed groups also activate regions implicated in cognitive control, even the adoptees who were monolingual French speakers at testing. Early exposure to a language, and/or delayed exposure to a subsequent language, continues to influence the neural processing of subsequently learned language sounds years later even in highly proficient, early-exposed users.

Whether brief early exposure to a language affects future language processing is unclear. Here Pierce et al. show that brain activity evoked by French pseudowords in monolingual French speaking Chinese adoptees is different from French children with no exposure to Chinese and similar to bilingual Chinese children.

Language development of internationally adopted children: Adverse early experiences outweigh the age of acquisition effect

We compared English language and cognitive skills between internationally adopted children (IA; mean age at adoption=2.24, SD=1.8) and their non-adopted peers from the US reared in biological families (BF) at two time points. We also examined the relationships between outcome measures and age at initial institutionalization, length of institutionalization, and age at adoption. On measures of general language, early literacy, and non-verbal IQ, the IA group performed significantly below their age-peers reared in biological families at both time points, but the group differences disappeared on receptive vocabulary and kindergarten concept knowledge at the second time point. Furthermore, the majority of children reached normative age expectations between 1 and 2 years post-adoption on all standardized measures. Although the age at adoption, age of institutionalization, length of institutionalization, and time in the adoptive family all demonstrated significant correlations with one or more outcome measures, the negative relationship between length of institutionalization and child outcomes remained most robust after controlling for the other variables. Results point to much flexibility and resilience in children's capacity for language acquisition as well as the potential primacy of length of institutionalization in explaining individual variation in IA children's outcomes.

LEARNING OUTCOMES

(1) Readers will be able to understand the importance of pre-adoption environment on language and early literacy development in internationally adopted children. (2) Readers will be able to compare the strength of the association between the length of institutionalization and language outcomes with the strength of the association between the latter and the age at adoption. (3) Readers will be able to understand that internationally adopted children are able to reach age expectations on expressive and receptive language measures despite adverse early experiences and a replacement of their first language with an adoptive language.

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.

The acquisition of accusative object clitics by IA children from China: evidence of early age effects?

The present study compared the performance of twenty-seven French-speaking internationally adopted (IA) children from China to that of twenty-seven monolingual non-adopted French-speaking children (CTL) matched for age, gender, and socioeconomic status on a Clitic Elicitation task. The IA children omitted significantly more accusative object clitics and made significantly more agreement errors using clitics than the CTL children. No other significant differences were found between the groups. The findings suggest that the adoptees may experience difficulties in morphosyntactic development possibly as a result of their delayed exposure to the adopted language.

Mapping the unconscious maintenance of a lost first language

Optimal periods during early development facilitate the formation of perceptual representations, laying the framework for future learning. A crucial question is whether such early representations are maintained in the brain over time without continued input. Using functional MRI, we show that internationally adopted (IA) children from China, exposed exclusively to French since adoption (mean age of adoption, 12.8 mo), maintained neural representations of their birth language despite functionally losing that language and having no conscious recollection of it. Their neural patterns during a Chinese lexical tone discrimination task matched those observed in Chinese/French bilinguals who have had continual exposure to Chinese since birth and differed from monolingual French speakers who had never been exposed to Chinese. They processed lexical tone as linguistically relevant, despite having no Chinese exposure for 12.6 y, on average, and no conscious recollection of that language. More specifically, IA participants recruited left superior temporal gyrus/planum temporale, matching the pattern observed in Chinese/French bilinguals. In contrast, French speakers who had never been exposed to Chinese did not recruit this region and instead activated right superior temporal gyrus. We show that neural representations are not overwritten and suggest a special status for language input obtained during the first year of development.