From rote learning to system building: acquiring verb morphology in children and connectionist nets (original) (raw)
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Morphological dissociations in the L2 acquisition of an inflectionally rich language
Eurosla Yearbook, 2009
This study investigates the validity of Dual-Mechanism Model in the mental representation of regular and irregular active past perfective verbs in adult non-native Greek. In this model, regular inflection is computed by a symbolic rule, while irregular words are fully stored in the lexicon. A nonce-probe elicitation task showed that both natives and non-natives generalized the regular affix -s, and more so in regular than in irregular perfective verb stems. Moreover, the degree of similarity of the nonce verbs to real ones did not affect the affixation of regulars. Dissimilar irregulars were affixed less often than similar ones by the intermediate learners but neither by the advanced learners, nor by the natives. Our findings support computation for regulars, as proposed by the Dual Mechanism Model, both in native and in non-native language acquisition. Yet, the model's claim for full storage of all irregular words is not verified.
Linguistics, 2000
This article reviews research on English past-tense acquisition to test the validity of the single mechanism model and the dual mechanism model, focusing on regular-irregular dissociation and semantic bias. Based on the review, it is suggested that in L1 acquisition, both regular and irregular verbs are governed by semantics; that is, early use of past tense forms are largely restricted to achievement verbs -regular or irregular. In contrast, some L2 acquisition studies show stronger semantic bias for regular past tense forms (House 2002). It is argued that L1 acquisition of the past-tense morphology can be accounted for adequately -without assuming dual mechanisms -by relying on connectionist-like input-based prototype formation as a mechanism for the development of tense-aspect morphology.
A neuroconstructivist model of past tense development and processing
Psychological Review
We present a neural network model of learning and processing the English past tense that is based on the notion that experience-dependent cortical development is a core aspect of cognitive development. During learning the model adds and removes units and connections to develop a task-specific final architecture. The model provides an integrated account of characteristic errors during learning the past tense, adult generalization to pseudoverbs, and dissociations between verbs observed after brain damage in aphasic patients. We put forward a theory of verb inflection in which a functional processing architecture develops through interactions between experience-dependent brain development and the structure of the environment, in this case, the statistical properties of verbs in the language. The outcome of this process is a structured processing system giving rise to graded dissociations between verbs that are easy and verbs that are hard to learn and process. In contrast to dual-mechanism accounts of inflection, we argue that describing dissociations as a dichotomy between regular and irregular verbs is a post hoc abstraction and is not linked to underlying processing mechanisms. We extend current single-mechanism accounts of inflection by highlighting the role of structural adaptation in development and in the formation of the adult processing system. In contrast to some single-mechanism accounts, we argue that the link between irregular inflection and verb semantics is not causal and that existing data can be explained on the basis of phonological representations alone. This work highlights the benefit of taking brain development seriously in theories of cognitive development.
Cognitive Psychology, 2019
The aim of the present work was to develop a computational model of how children acquire inflectional morphology for marking person and number; one of the central challenges in language development. First, in order to establish which putative learning phenomena are sufficiently robust to constitute a target for modelling, we ran large-scale elicited production studies with native learners of Finnish (N = 77; 35-63 months) and Polish (N = 81; 35-59 months), using a novel method that, unlike previous studies, allows for elicitation of all six person/number forms in the paradigm (first, second and third person; singular and plural). We then proceeded to build and test a connectionist model of the acquisition of person/number marking which not only acquires near adult-like mastery of the system (including generalisation to unseen items), but also yields all of the key phenomena observed in the elicited-production studies; specifically, effects of token frequency and phonological neighbourhood density of the target form, and a pattern whereby errors generally reflect the replacement of low frequency targets by higher-frequency forms of the same verb, or forms with the same person/number as the target, but with a suffix from an inappropriate conjugation class. The findings demonstrate that acquisition of even highly complex systems of inflectional morphology can be accounted for by a theoretical model that assumes rote storage and phonological analogy, as opposed to formal symbolic rules.