Language acquisition as skill learning

Functional dissociation of the language network and other cognition in early childhood

Is language distinct from other cognition during development? Does neural machinery for language emerge from general-purpose neural mechanisms, becoming tuned for language after years of experience and maturation? Answering these questions will shed light on the origins of domain-specificity in the brain. We address these questions using precision fMRI, scanning young children (35 months to 9 years of age) on an auditory language localizer, spatial working memory localizer (engaging the domain-general multiple demand [MD] network), and a resting-state scan. We create subject-specific functional regions of interest for each network and examine their selectivity, specificity, and functional connectivity. We find young children show domain-specific, left-lateralized language activation, and that the language network is not responsive to domain-general cognitive load. Additionally, the cortically adjacent MD network is selective to cognitive load, but not to language. These networks show higher within versus between-network functional connectivity. This connectivity is stable across ages (examined cross-sectionally and longitudinally), whereas language responses increase with age and across time within subject, reflecting a domain-specific developmental change. Overall, we provide evidence for a double dissociation of the language and MD network throughout development, in both their function and connectivity. These findings suggest that domain-specificity, even for uniquely human cognition like language, develops early and distinctly from mechanisms that presumably support other human cognition.

Associations between early efficiency in language processing and language and cognitive outcomes in children born full term and preterm: similarities and differences

Associations between children's early language processing efficiency and later verbal and non-verbal outcomes shed light on the extent to which early information processing skills support later learning across different domains of function. Examining whether the strengths of associations are similar in typically developing and at-risk populations provides an additional lens into the varying routes to learning that children may take across development. In this follow-up study, children born full-term (FT, n = 49) and preterm (PT, n = 45, ≤32 weeks gestational age, birth weight <1800 g) were assessed in the Looking While Listening (LWL) task at 18 months (corrected for degree of prematurity in PT group). This eye-tracking task assesses efficiency of real-time spoken language comprehension as accuracy and speed (RT) of processing. At 4 ½ years, children were assessed on standardized tests of receptive vocabulary, expressive language, and non-verbal IQ. Language processing efficiency was associated with both language outcomes (r2-change: 7.0-19.7%, p < 0.01), after covariates. Birth group did not moderate these effects, suggesting similar mechanisms of learning in these domains for PT and FT children. However, birth group moderated the association between speed and non-verbal IQ (r2-change: 4.5%, p < 0.05), such that an association was found in the PT but not the FT group. This finding suggests that information processing skills reflected in efficiency of real-time language processing may be recruited to support learning in a broader range of verbal and non-verbal domains in the PT compared to the FT group.

Neuroplasticity enables bio-cultural feedback in Paleolithic stone-tool making

Stone-tool making is an ancient human skill thought to have played a key role in the bio-cultural co-evolutionary feedback that produced modern brains, culture, and cognition. To test the proposed evolutionary mechanisms underpinning this hypothesis we studied stone-tool making skill learning in modern participants and examined interactions between individual neurostructural differences, plastic accommodation, and culturally transmitted behavior. We found that prior experience with other culturally transmitted craft skills increased both initial stone tool-making performance and subsequent neuroplastic training effects in a frontoparietal white matter pathway associated with action control. These effects were mediated by the effect of experience on pre-training variation in a frontotemporal pathway supporting action semantic representation. Our results show that the acquisition of one technical skill can produce structural brain changes conducive to the discovery and acquisition of additional skills, providing empirical evidence for bio-cultural feedback loops long hypothesized to link learning and adaptive change.

Literacy improves the comprehension of object relatives

While there is a considerable body of research indicating that the acquisition of literacy has profound effects on many aspects of language and cognition, to our knowledge, very little is known about its effects on morphosyntax. In this paper, we explore the effects of literacy on the comprehension of Spanish object relative clauses, a structure which is typically acquired by literate children about the age of 10, i.e., after a considerable amount of exposure to written language. We tested three groups of native Spanish speakers (semi-literates, late-literates and high-literates) using a picture selection task. Subject relatives were used as a control condition. All three groups performed at ceiling on subject relatives (group means of 95% or above). In contrast, we observed very large differences in performance on object relatives, with the semi-literate group performing at chance (51% correct) and the late-literate group slightly above chance (65% correct). Performance in the high-literate group was much better, although not quite at ceiling (82% correct). The results appear to support the hypothesis that literacy helps in the acquisition of some aspects of grammar. This could be partly due to differences in IQ, metalinguistic awareness, working memory and/or executive functioning. The results are also consistent with the 'training wheels' hypothesis (Dąbrowska, 2020), according to which the availability of written representations facilitates the acquisition of difficult structures by easing memory load and enabling speakers to process sentences at their own pace.

Models of Language and Multiword Expressions

Traditional accounts of language postulate two basic components: words stored in a lexicon, and rules that govern how they can be combined into meaningful sentences, a grammar. But, although this words-and-rules framework has proven itself to be useful in natural language processing and cognitive science, it has also shown important shortcomings when faced with actual language use. In this article, we review evidence from language acquisition, sentence processing, and computational modeling that shows how multiword expressions such as idioms, collocations, and other meaningful and common units that comprise more than one word play a key role in the organization of our linguistic knowledge. Importantly, multiword expressions straddle the line between lexicon and grammar, calling into question how useful this distinction is as a foundation for our understanding of language. Nonetheless, finding a replacement for the foundational role the words-and-rules approach has played in our theories is not straightforward. Thus, the second part of our article reviews and synthesizes the diverse approaches that have attempted to account for the central role of multiword expressions in language representation, acquisition, and processing.

Toward a “Standard Model” of Early Language Learning

A standard model is a theoretical framework that synthesizes observables into a quantitative consensus. Have researchers made progress toward this kind of synthesis for children’s early language learning? Many computational models of early vocabulary learning assume that individual words are learned through an accumulation of environmental input. This assumption is also implicit in empirical work that emphasizes links between language input and learning outcomes. However, models have typically focused on average performance, whereas empirical work has focused on variability. To model individual variability, we relate the tradition of research on accumulator models to item response theory models from psychometrics. This formal connection reveals that currently available data sets do not allow researchers to test the resulting models fully, illustrating a critical need for theory to contribute to shaping new data collection and creating and testing an eventual standard model.

Statistically Induced Chunking Recall: A Memory-Based Approach to Statistical Learning

The computations involved in statistical learning have long been debated. Here, we build on work suggesting that a basic memory process, chunking, may account for the processing of statistical regularities into larger units. Drawing on methods from the memory literature, we developed a novel paradigm to test statistical learning by leveraging a robust phenomenon observed in serial recall tasks: that short-term memory is fundamentally shaped by long-term distributional learning. In the statistically induced chunking recall (SICR) task, participants are exposed to an artificial language, using a standard statistical learning exposure phase. Afterward, they recall strings of syllables that either follow the statistics of the artificial language or comprise the same syllables presented in a random order. We hypothesized that if individuals had chunked the artificial language into word-like units, then the statistically structured items would be more accurately recalled relative to the random controls. Our results demonstrate that SICR effectively captures learning in both the auditory and visual modalities, with participants displaying significantly improved recall of the statistically structured items, and even recall specific trigram chunks from the input. SICR also exhibits greater test-retest reliability in the auditory modality and sensitivity to individual differences in both modalities than the standard two-alternative forced-choice task. These results thereby provide key empirical support to the chunking account of statistical learning and contribute a valuable new tool to the literature.

Age of Acquisition of Mandarin Modulates Cortical Thickness in High-Proficient Cantonese-Mandarin Bidialectals

Previous studies showed that the onset age of second language acquisition (AoA-L2) can modulate brain structure of bilinguals. However, the underlying mechanism of anatomical plasticity induced by AoA-L2 is still a question in debate. In order to explore the issue, we recruited two groups of native Cantonese-Mandarin speakers, the early group began to speak in Mandarin at about 3.5 and the late group at about 6.5 years old. In addition, the early group had earlier experience in reading Chinese characters than the late group did. Through estimating the cortical thickness (CT), we found that (1) compared with the late group, the early group had thicker CT in the lateral occipital region, left middle temporal gyrus, and left parahippocampal region, which are all involved in visuospatial processing, probably reflecting the effect induced by the earlier or later experiences in processing the characters of Chinese for the two groups; and (2) compared with the late group, the early group had thicker CT in left superior parietal region, which is believed to be involved in language switching, maybe for the early group had the earlier experience in switching back and forth between Cantonese and Mandarin and therefore recruited the executive control network earlier. Our findings revealed the effects of the AoA-L2 in oral language acquisition as well as in written language acquisition as the main determinants of bilingual language structural representation in human brain.

More evidence from over 1.1 million subjects that the critical period for syntax closes in late adolescence

The ability to attain native-like proficiency of a second language is heavily dependent on the age at which learning begins. However, the exact properties of this phenomenon remain unclear, and the literature is divided. Recently, Hartshorne, Tenenbaum, & Pinker presented a novel computational analysis of over 600,000 subjects, estimating that the ability to learn syntax drops at 17.4 years of age [Hartshorne, J. K., Tenenbaum, J. B., & Pinker, S. (2018). A critical period for second language acquisition: Evidence from 2/3 million English speakers. Cognition, 177, 263-277]. However, the novelty of the dataset and analyses raises questions and suggests caution [Frank, M. C. (2018). With great data comes great (theoretical) opportunity. Trends in cognitive sciences, 22(8), 669-671]. In the present paper, we address several such concerns by employing improved psychometric measurement, calculating confidence intervals, and considering alternative models. We also present data from an additional 466,607 subjects. The results support the prior report of a sharp decline in the ability to learn syntax, commencing at the tail end of adolescence.

Recitation as a structured intervention to enhance the long-term verbatim retention and gist recall of complex texts in kindergarteners

Recitation is an effective way for children to become familiar with basic blocks of knowledge. It is not clear, however, whether repeated structured exposure to complex texts via listening or active reciting benefits the ability of kindergarteners to retain verbal material in long-term memory verbatim and as content. Here, we tested the effectiveness of teaching longer texts to kindergarteners by repeated exposure in terms of long-term retention (6 months). A set of 28 rhyming sentences (224 words) were introduced, 3 in each session, and the increasingly longer text was practiced by either voiced recitation or listening. The rhymes were in a literary language, and word meaning in each new rhyme was elaborated when first introduced. Both groups (recitation and listening) showed good long-term retention, but the recitation group outperformed the listening group when assessed at 24 h, 1 month, and 6 months postintervention in terms of the recall rate, error rate, number of prompts required, and sequence fidelity. In the later assessments, the reciting group was the more fluent group in producing the rhymes. Moreover, at 6 months postintervention, the gist (content) of the rhymes and the meaning of vocabulary items from the texts were robustly retained, with an advantage for the recitation group. Thus, practice in affording multiple repetitions, specifically active recitation, resulted in fluent, effortless, and accurate recall of statements and their content. We propose that these results support the notion that repetition-based practice may promote the mastery of complex verbal material by enabling better engagement of procedural memory, that is, by promoting "proceduralization" processes.

When Too Many Vowels Impede Language Processing: An Eye-Tracking Study of Danish-Learning Children

Research has suggested that Danish-learning children lag behind in early language acquisition. The phenomenon has been attributed to the opaque phonetic structure of Danish, which features an unusually large number of non-consonantal sounds (i.e., vowels and semivowels/glides). The large number of vocalic sounds in speech is thought to provide fewer cues to word segmentation and to make language processing harder, thus hindering the acquisition process. In this study, we explored whether the presence of vocalic sounds at word boundaries impedes real-time speech processing in 24-month-old Danish-learning children, compared to word boundaries that are marked by consonantal sounds. Using eye-tracking, we tested children's real-time comprehension of known consonant-initial and vowel-initial words when presented in either a consonant-final carrier phrase or in a vowel-final carrier phrase, thus resulting in the four boundary types C#C, C#V, V#C, and V#V. Our results showed that the presence of vocalic sounds around a word boundary-especially before-impedes processing of Danish child-directed sentences.

Speech-language development as proceduralization and skill learning: Implications for assessment and intervention

PURPOSE

This article considers how speech-language development can be viewed as proceduralization and skill learning. Viewing speech-language development in this way has important implications for the assessment and treatment of individuals with speech-language disorders.

METHOD

Topics discussed are Ullman's (2016) distinction between the procedural and declarative memory systems, speech-language development as proceduralization and skill learning, and implications for assessment and intervention.

CONCLUSION

Norm-referenced measures provide a good measure of deliberative speech-language processes whereas social conversations and discourses about familiar topics with familiar listeners provide the best indication of proceduralized speech-language processes. Intervention goals and planning need to consider which speech-language operations should be proceduralized and which ones will primarily require deliberative processing. Additional research and clinical application of these ideas are clearly needed to develop more precise criteria to define the line of demarcation between deliberative and proceduralized speech-language processes.