Arnon, I. & Christiansen, M. H. (2014). Chunk-based Language Acquisition. (original) (raw)

Can Chunk Size Differences Explain Developmental Changes in Lexical Learning

In three experiments, we investigated Hebb repetition learning (HRL) differences between children and adults, as a function of the type of item (lexical vs. sub-lexical) and the level of item-overlap between sequences. In a first experiment, it was shown that when non-repeating and repeating (Hebb) sequences of words were all permutations of the same words, HRL was slower than when the sequences shared no words. This item-overlap effect was observed in both children and adults. In a second experiment, we used syllable sequences and we observed reduced HRL due to item-overlap only in children. The findings are explained within a chunking account of the HRL effect on the basis of which we hypothesize that children, compared with adults, chunk syllable sequences in smaller units. By hypothesis, small chunks are more prone to interference from anagram representations included in the filler sequences, potentially explaining the item-overlap effect in children. This hypothesis was tested in a third experiment with adults where we experimentally manipulated the chunk size by embedding pauses in the syllable sequences. Interestingly, we showed that imposing a small chunk size caused adults to show the same behavioral effects as those observed in children. Departing from the analogy between verbal HRL and lexical development, the results are discussed in light of the less-is-more hypothesis of age-related differences in language acquisition.

Computational investigations of multiword chunks in language learning

Second-language learners rarely arrive at native proficiency in a number of linguistic domains, including morphological and syntactic processing. Previous approaches to understanding the different outcomes of first-vs. second-language learning have focused on cognitive and neural factors. In contrast, we explore the possibility that children and adults may rely on different linguistic units throughout the course of language learning, with specific focus on the granularity of those units. Following recent psycholinguistic evidence for the role of multiword chunks in on-line language processing, we explore the hypothesis that children rely more heavily on multiword units in language learning than do adults learning a second language. To this end, we take an initial step towards using large-scale, corpus-based computational modeling as a tool for exploring the granularity of speakers' linguistic units. Employing a computational model of language learning, the Chunk-based Learner (CBL), we compare the usefulness of chunk-based knowledge in accounting for the speech of second-language learners vs. children and adults speaking their first language. Our findings suggest that while multiword units are likely to play a role in second-language learning, adults may learn less useful chunks, rely on them to a lesser extent, and arrive at them through different means than children learning a first language.

A Merge-based theory of child language acquisition

A Recap: Structure-building models. Since theory-internal considerations define Move-based (Internal merge) functional categories as the only type of phrasal projections which could serve as potential landing-sites for move-based elements displaced from lower down within the base-generated syntactic structure – e.g., A-movement such as passives ("The apple was eaten by [John (ate the apple)]"), or raising ("Some work does seem to remain"; "(There) does seem to remain (some work)") – as a consequence, any structure-building which calls for an exclusive lexical stage-1 before a functional stage-2 means that early child speech simply lacks the ability to generate and host elements derived via movement operation. Particularly, the theoretical specifier position of a functional head is seen as projecting for the sole purpose of hosting moved elements. Hence, according to a structure-building model, early child utterances at the early multi-word lexical stage-1 simply lack movement. In addition to the lack of A-movement talked about by Borer and Wexler, Radford considers the absence of a second kind of movement, termed f-movement since it involves movement of a base-generated item into a higher f(unctional) position — namely, a head or specifier position within a functional category (DP, TP, CP) (e.g., auxiliary inversion from T to C ["Does [he (does) like it]?"]). This glass-ceiling of move-based morphosyntax suggests that all early multi-word utterances (usually associated with children aged 18 to 23 months, ±20%) involve flat structure-building elements (N, V) not motivated by movement: what Radford terms bricolage. These prosaic bricolage structures are considered lexical/thematic in nature, with any observed early morphology being relegated to lexicalization (such as derivational morphology, or formulaic chunking) whereby the fixed morpheme involved is said to be incorporated, unsegmented and undecomposed within the lexical stem. When true inflectional morphology emerges, it follows a gradual growth trajectory with the simple lexical noun and verb inflections emerging first: e.g., plural [N + [{s}]], gerund [V + [{ing}]], [V + [{en}]], with the later onset of more formal inflections associated with functional phrases DP (e.g., possessive {'s}, Case on pronouns ("he" vs "him"), and TP (e.g., Agreement {s}, and Tense {ed}). (Radford & Galasso).

Lexical segmentation and vocabulary growth in early language acquisition

Journal of Child Language, 1993

The identification of appropriate lexical segmentations of the speech signal constitutes a problem for the language learner and the child language researcher alike. Articulatory precision and fluency criteria for identifying formulaic expressions, sub-lexical forms and target lexemes in linguistic productions are defined and applied to the analysis of two Danish children's language development between the ages of 1;0 and 2;0. The results of this analysis are compared to the results of applying standard distributional and frequency criteria in the tabulation of mean length of utterance and vocabulary profiles for both standard and non-standard lexical segmentations. It is argued that although the two methods yield converging profiles of development during the latter part of the period studied, articulatory precision and fluency criteria offer a more powerful tool for identifying alternative segmentation strategies in early language acquisition. Profiles of vocabulary development for these two children suggest that the solution to the segmentation problem may be an important trigger for their vocabulary spurts.

Learning words and learning sounds: Advances in language development

British journal of psychology (London, England : 1953), 2016

Phonological development is sometimes seen as a process of learning sounds, or forming phonological categories, and then combining sounds to build words, with the evidence taken largely from studies demonstrating 'perceptual narrowing' in infant speech perception over the first year of life. In contrast, studies of early word production have long provided evidence that holistic word learning may precede the formation of phonological categories. In that account, children begin by matching their existing vocal patterns to adult words, with knowledge of the phonological system emerging from the network of related word forms. Here I review evidence from production and then consider how the implicit and explicit learning mechanisms assumed by the complementary memory systems model might be understood as reconciling the two approaches.