The acquisition of English noun and verb morphology is modeled using a single-system connectionist network. The network is trained to produce the plurals and past tense forms of a large corpus of monosyllabic English nouns and verbs. The developmental trajectory of network performance is analyzed in detail and is shown to mimic a number of important features of the acquisition of English noun and verb morphology in young children. These include an initial error-free period of performance on both nouns and (...) verbs followed by a period of intermittent over-regularization of irregular nouns and verbs. Errors in the model show evidence of phonological conditioning and frequency effects. Furthermore, the network demonstrates a strong tendency to regularize denominal verbs and deverbal nouns and masters the principles of voicing assimilation. Despite their incorporation into a single-system network, nouns and verbs exhibit some important differences in their profiles of acquisition. Most importantly, noun inflections are acquired earlier than verb inflections. The simulations generate several empirical predictions that can be used to evaluate further the suitability of this type of cognitive architecture in the domain of inflectional morphology. (shrink)

How many words is a bilingual 2-year-old supposed to know or say in each of her languages? Speech and language therapists or researchers lack the tools to answer this question, because several factors have an impact on bilingual language skills: gender, amount of exposure, mode of acquisition, socio-economic status and the distance between L1 and L2. Unfortunately, these factors are usually studied separately, making it difficult to evaluate their weight on a unique measure of vocabulary. The present study measures the (...) contribution of the following factors to the vocabulary scores of bilingual toddlers: i) gender; ii) sibling ranking; iii) relative amount of exposure to each language; iv) mode of exposure; v) SES; vi) linguistic distance; vii) language spoken between parents. Close to the child’s second birthday, parents of 278 UK-based bilinguals completed successively: a 100-word version of the Oxford-CDI, the CDI in the child’s Additional Language, a family questionnaire, and the Language Exposure Questionnaire. Thirty-six British-English-AL pairs were considered, with languages contrasted on a second-language-learning scale : for example, Dutch and French are close to British-English, while Polish or Cantonese are more distant. Data from the corpus were included in two mixed-effect models, one with the English scores in comprehension as the dependent variable, and the other with production scores. The seven factors listed above were included as predictors. The amount of English exposure was the strongest predictor of comprehension scores = 9.35, p <.005, β = 0.02, t = 3.08, p <.005), followed by the language that parents speak between themselves = 14.94, p <.001, β = 1.37, t = 3.76, p <.0005), linguistic distance = 6.92, p <.01, β = -0.74, t = -2.66, p <.01) and age = 4.86, p <.05, β = 0.55, t = 2.17, p <.05). In production, gender = 13.57, p <.0005, β = -0.91, t = -03.72, p <.0005), amount of exposure to English = 13.57, p <.0005, β = -0.91, t = -03.72, p <.0005), the language that parents speak between themselves = 11.85, p <.005, β = 1.09, t = 3.41, p <.001), and the mother’s occupation = 4.51, p <.05, β = 0.63, t = 2.13, p <.05) were the significant predictors. The more English parents use to address one another, the more English words the child says and understands. This surprising result could be simply explained by the fact that parents who speak English together are also more likely to speak English to their child. The main results of this study is that linguistic distance is a powerful predictor of toddlers’ vocabulary in English, with children learning two close languages growing their vocabulary faster than those learning distant languages. (shrink)