Lexical Acquisition Research Articles

Word Learning in Infant- and Adult-Directed Speech

Infant-directed speech (IDS), compared with adult-directed speech (ADS), is characterized by a slower rate, a higher fundamental frequency, greater pitch variations, longer pauses, repetitive intonational structures, and shorter sentences. Despite studies on the properties of IDS, there is no direct demonstration of its effects for word learning in infants. This study examined whether 21- and 27-month-old children learned novel words better in IDS than in ADS. Two major findings emerged. First, 21-month-olds reliably learned words only in the IDS condition, although children with relatively larger vocabulary than their peers learned in the ADS condition as well. Second, 27-month-olds reliably learned the words in the ADS condition. These results support the implicitly held assumption that IDS does in fact facilitate word mapping at the start of lexical acquisition and that its influence wanes as language development proceeds.

Descobrindo novas palavras no fluxo da fala: o impacto da prosódia na aquisição lexical

Discute-se o papel da informação prosódica na aquisição lexical por crianças adquirindo o português do Brasil, tendo por foco elementos da categoria lexical ADJ(etivo). Assume-se que a fala se organiza em constituintes prosódicos hierarquicamente dispostos, parcialmente sensíveis à estrutura sintática, e defende-se que adultos e crianças usam pistas prosódicas para o reconhecimento da posição do adjetivo no DP (Experimento 1), identificam pseudopalavras como novos adjetivos (Experimento 2) e atribuem valor subjetivo ao realce prosódico do adjetivo anteposto a N (Experimento 3). Discutem-se os resultados obtidos à luz de modelos de processamento comprometidos com a aquisição de linguagem.

Classification of L2 Vocabulary Learning Strategies: Evidence from Exploratory and Confirmatory Factor Analyses

This research presents a classification theory for the L2 vocabulary learning strategies. Based on the exploratory and confirmatory factor analyses of strategies that adult Chinese English learners used, this theory identifies six categories, four of which are related to the cognitive process in lexical acquisition and the other two are metacognitive and affective factors. Compared to other theories on language learning strategies, the uniqueness of this theory lies in that the cognitive factors correspond to the essential steps learners take in acquiring new words. This research does not support that a memory factor or a social factor exists independently in vocabulary learning strategies.

Phrasal prosody constrains word segmentation in French 16-month-olds.

Infants who are in the process of acquiring their mother tongue have to find a way of segmenting the continuous speech stream into word-sized units. We present an experiment showing that French 16-month-olds are able to exploit phonological phrase boundaries in order to constrain lexical access. Using the conditioned head-turning technique, we showed that infants trained to turn their head for a bisyllabic word responded more often to sentences that contained this word, than to sentences that contained both syllables of this word separated by a phonological phrase boundary. We compare these results with similar results obtained with English-speaking infants, and discuss their implication for lexical and syntactic acquisition.

Avaliação do vocabulário expressivo em crianças surdas usuárias da Língua Brasileira de Sinais

OBJETIVO: investigar o desempenho de crianças surdas usuárias da Língua Brasileira de Sinais em teste de vocabulário expressivo. MÉTODO: a amostra foi composta por 64 sujeitos (32 crianças no grupo estudo e 32 no grupo controle) que foram divididos em 4 grupos por idade (5, 6 , 7 e 8 anos). Todas as crianças foram submetidas ao Teste de Linguagem Infantil ABFW - Vocabulário. As respostas foram classificadas em designação do vocábulo usual (DVU), não-designação (ND) e processo de substituição (PS), de acordo com a proposta da autora da prova. RESULTADOS: na maioria dos campos conceituais, o grupo de deficientes auditivos obteve pior desempenho em relação ao grupo controle. Verificou-se que nos dois grupos estudados os piores desempenhos ocorreram nas categorias locais, alimentos e vestuário, em todas as idades. Em ambos os grupos verificou-se melhor desempenho nas crianças de 5 anos de idade, em comparação às demais crianças. Também em ambos os grupos estudados, os processos de substituição foram observados com maior freqüência no campo locais e com menor freqüência em formas e cores. Não houve diferença significante entre as idades. CONCLUSÃO: os campos conceituais com maiores índices de acerto nas crianças surdas usuárias da Língua Brasileira de Sinais foram profissões, brinquedos e instrumentos musicais e móveis e utensílios domésticos. Apesar das diferenças quantitativas observadas em relação aos grupos, observou-se grande similaridade qualitativa quanto às respostas obtidas, sugerindo-se um processo evolutivo semelhante na aquisição lexical dos grupos.

Why Brush Your Teeth Is Better Than Teeth – Children's Word Production Is Facilitated in Familiar Sentence-Frames

Adult production is influenced by the larger linguistic contexts in which words appear. Children, like adults, hear words in recurring linguistic contexts, but little is known on the effect of that context on their speech. We look at the production of irregular plurals in English (e.g., mice, feet) to argue that children attend to the larger phrases words appear in and make use of that distributional knowledge in production. We assess the role of linguistic context by comparing irregular plurals elicited with a general question (What are all these?) versus a lexically specific frequent frame (e.g., Three blind —). In study 1, 4;6 year-olds produced many more correct irregulars after lexically specific frequent frames (72%) than after a general question (32%). Corpus data on spontaneous speech offered analogous findings: Children did not overregularize irregular plurals after lexically-specific frames. In study 2, we confirm children's sensitivity to the relation between particular words and phrases: A familiar frame (So many) enhanced production (52%) but not as much as the lexically specific frames in Study 1. Children's word production is affected by the larger patterns words appear in. Consequently, studies of lexical and morphological acquisition need to take linguistic context into account when assessing children's abilities. This has implications for models of both lexical and morphological acquisition.

Information retrieval with semantic memory model

Psycholinguistic theories of semantic memory form the basis of understanding of natural language concepts. These theories are used here as an inspiration for implementing a computational model of semantic memory in the form of semantic network. Combining this network with a vector-based object-relation-feature value representation of concepts that includes also weights for confidence and support, allows for recognition of concepts by referring to their features, enabling a semantic search algorithm. This algorithm has been used for word games, in particular the 20-question game in which the program tries to guess a concept that a human player thinks about. The game facilitates lexical knowledge validation and acquisition through the interaction with humans via supervised dialog templates. The elementary linguistic competencies of the proposed model have been evaluated assessing how well it can represent the meaning of linguistic concepts. To study properties of information retrieval based on this type of semantic representation in contexts derived from on-going dialogs experiments in limited domains have been performed. Several similarity measures have been used to compare the completeness of knowledge retrieved automatically and corrected through active dialogs to a “golden standard”. Comparison of semantic search with human performance has been made in a series of 20-question games. On average results achieved by human players were better than those obtained by semantic search, but not by a wide margin.

The independent effects of phonotactic probability and neighbourhood density on lexical acquisition by preschool children

The goal of this research was to disentangle effects of phonotactic probability, the likelihood of occurrence of a sound sequence, and neighbourhood density, the number of phonologically similar words, in lexical acquisition. Two-word learning experiments were conducted with 4-year-old children. Experiment 1 manipulated phonotactic probability while holding neighbourhood density and referent characteristics constant. Experiment 2 manipulated neighbourhood density while holding phonotactic probability and referent characteristics constant. Learning was tested at two time points (immediate vs. retention) in both a naming and referent identification task, although only data from the referent identification task were analysed due to poor performance in the naming task. Results showed that children were more accurate in learning rare sound sequences than common sound sequences and this was consistent across time points. In contrast, the effect of neighbourhood density varied by time. Children were more accurate in learning sparse sound sequences than dense sound sequences at the immediate test point but accuracy for dense sound sequences significantly improved by the retention test without further training. It was hypothesised that phonotactic probability and neighbourhood density influenced different cognitive processes that underlie lexical acquisition.

Developmental parallels in diachronic and ontogenetic grammaticalization: Existential there as a test case

This paper examines the potential parallel between the ontogenetic and historical processes of grammaticalization of existential there . Taking Christopher Johnson's (Constructional grounding: The role of interpretational overlap in lexical and constructional acquisition, University of California, Berkeley, 1999, Constructional grounding: On the relation between deictic and existential there -constructions in acquisition, 2001, Developmental reinterpretation in first language acquisition, 2005) analysis of Child English as a starting point, the article tests the relevance of his theory of constructional grounding or developmental reinterpretation to the diachronic evolution of existential there -constructions in the earliest stages of the English language. The data show that, as in the case of child language acquisition, the existential pattern ( There's a dog in the yard ) is historically grounded in the deictic construction ( There's the dog running around ) and that double-locative overlap structures played a key role in the process of change.

Lexical stress and phonetic processing in word learning in20‐ to 24‐month‐old English‐learning children

To investigate the interaction between segmental and supra-segmental stress-related information in early word learning, two experiments were conducted with 20- to 24-month-old English-learning children. In an adaptation of the object categorization study designed by Nazzi and Gopnik (2001), children were presented with pairs of novel objects whose labels differed by their initial consonant (Experiment 1) or their medial consonant (Experiment 2). Words were produced with a stress initial (trochaic) or a stress final (iambic) pattern. In both experiments successful word learning was established when the to-be-remembered contrast was embedded in a stressed syllable, but not when embedded in unstressed syllables. This was independent of the overall word pattern, trochaic or iambic, or the location of the phonemic contrast, word-initial or -medial. Results are discussed in light of the use of phonetic information in early lexical acquisition, highlighting the role of lexical stress and ambisyllabicity in early word processing.

Phonology and lexicon in a cross-linguistic perspective: the importance of phonetics – a commentary on Stoel-Gammon's ‘Relationships between lexical and phonological development in young children’*

In her interesting article, Stoel-Gammon (this issue) reviews studies concerning the interactions between lexical and phonological development. While the focus of the review is on vocabulary production from children acquiring American English, she also suggests that cross-linguistic research be undertaken to examine how universal and language-specific properties affect the interaction between lexical and phonological acquisition. In this regard, Stoel-Gammon referred to the study of Bleses et al. (2008) who found differences in receptive vocabulary development across languages, based on norming studies for the Communicative Development Inventories (Fenson, Marchman, Thal, Dale, Reznick & Bates, 2007). Bleses et al. showed that Danish children were slower in the early comprehension of words (and phrases). It was hypothesized that the phonetic structure of Danish may account for the difference in receptive vocabulary skills in this population (Bleses & Basbøll, 2004).

Differentiating word learning processes may yield new insights – a commentary on Stoel-Gammon's ‘Relationships between lexical and phonological development in young children’

Stoel-Gammon (this issue) states that ‘from birth to age 2 ; 6, the developing phonological system affects lexical acquisition to a greater degree than lexical factors affect phonological development’ (this issue). This conclusion is based on a wealth of data; however, the available data are somewhat limited in scope, focusing on rather holistic measures of the phonological and lexical systems (e.g. production accuracy, number of words known). Stoel-Gammon suggests a number of important avenues to pursue, but does not discuss a critical one that is emerging in the broader literature on word learning. Specifically, recent connectionist models and adult word learning research provide evidence that greater differentiation of the cognitive processes that underlie word learning yields new insights (Leach & Samuel, 2007). This approach may be fruitful for future investigations of the relationship between phonological and lexical development in young children.

The Relationship Between Phonological Memory, Phonological Sensitivity, and Incidental Word Learning

This study investigated the cognitive abilities needed to succeed at incidental word learning, specifically by examining the role of phonological memory and phonological sensitivity in novel word learning by 4-year-olds who were typically developing. Forty 4-year-olds were administered a test of nonword repetition (to investigate phonological memory), rhyming and phoneme alliteration tasks (to investigate phonological sensitivity), and an incidental word learning task (via a computer-based presentation of a cartoon story). A multiple regression analysis revealed that nonword repetition scores did not contribute significantly to incidental word learning. Phonological sensitivity scores were significant predictors of incidental word learning. These findings provide support for a model of lexical acquisition in which phonological knowledge plays an important role.

Bilingual lexical interactions in an unsupervised neural network model

In this paper we present an unsupervised neural network model of bilingual lexical development and interaction. We focus on how the representational structures of the bilingual lexicons can emerge, develop, and interact with each other as a function of the learning history. The results show that: (1) distinct representations for the two lexicons can develop in our network when the two languages are learned simultaneously; (2) the representational structure is highly dependent on the onset time of the second language (L2) learning if the two languages are learned sequentially; and (3) L2 representation becomes parasitic on the representation of the first language when the learning of L2 occurs late. The results suggest a dynamic developmental picture for bilingual lexical acquisition: the acquisition of two languages entails strong competition in a highly interactive context and involves limited plasticity as a function of the timing of L2 learning.

Automatic lexical classification: bridging research and practice

Natural language processing (NLP)--the automatic analysis, understanding and generation of human language by computers--is vitally dependent on accurate knowledge about words. Because words change their behaviour between text types, domains and sub-languages, a fully accurate static lexical resource (e.g. a dictionary, word classification) is unattainable. Researchers are now developing techniques that could be used to automatically acquire or update lexical resources from textual data. If successful, the automatic approach could considerably enhance the accuracy and portability of language technologies, such as machine translation, text mining and summarization. This paper reviews the recent and on-going research in automatic lexical acquisition. Focusing on lexical classification, it discusses the many challenges that still need to be met before the approach can benefit NLP on a large scale.

A Probabilistic Computational Model of Cross‐Situational Word Learning

Words are the essence of communication: They are the building blocks of any language. Learning the meaning of words is thus one of the most important aspects of language acquisition: Children must first learn words before they can combine them into complex utterances. Many theories have been developed to explain the impressive efficiency of young children in acquiring the vocabulary of their language, as well as the developmental patterns observed in the course of lexical acquisition. A major source of disagreement among the different theories is whether children are equipped with special mechanisms and biases for word learning, or their general cognitive abilities are adequate for the task. We present a novel computational model of early word learning to shed light on the mechanisms that might be at work in this process. The model learns word meanings as probabilistic associations between words and semantic elements, using an incremental and probabilistic learning mechanism, and drawing only on general cognitive abilities. The results presented here demonstrate that much about word meanings can be learned from naturally occurring child-directed utterances (paired with meaning representations), without using any special biases or constraints, and without any explicit developmental changes in the underlying learning mechanism. Furthermore, our model provides explanations for the occasionally contradictory child experimental data, and offers predictions for the behavior of young word learners in novel situations.

Adult offer, word-class, and child uptake in early lexical acquisition

How do adults offer new words from different parts of speech? This study examined the offers in book-reading interactions for 48 dyads (parents and children aged 2- to 5-years-old). The parents relied on fixed syntactic frames, final position, and emphatic stress to highlight unfamiliar words. As they talked to their children about the referent objects, events, or scenes, they also linked new words to other terms in the pertinent semantic domain, thereby presenting further information about possible meanings. Children attended to new words, often repeating them in the next turn, and, as they got older, they too related new words to familiar terms as they talked about their referents with their parents. These data add further evidence that interaction in conversation supports the process of language acquisition.

Spelling impairments in Italian dyslexic children: Phenomenological changes in primary school

IntroductionAlthough spelling difficulties are constantly associated with developmental dyslexia, they have been largely neglected by the majority of studies in this area. This study analyzes spelling impairments in developmental dyslexia across school grades in Italian, a language with high grapheme-to-phoneme correspondence. MethodsThe performances of 33 Italian dyslexic children attending Grades 3 and 5 were compared with those of age-matched control participants. Writing abilities were investigated through a spelling test that included regular words with one-sound-to-one-letter correspondence, regular words requiring the application of context-sensitive conversion rules, words with unpredictable transcription and nonwords with one-sound-to-one-letter correspondence. ResultsBoth accuracy and error analyses indicate that the spelling impairment assumes different characteristics at different grades: Grade 3 children showed an undifferentiated spelling deficit (involving regular words, regular nonwords and words with unpredictable spelling), whereas the fifth graders were prevalently impaired in writing words with unpredictable transcription. The error analysis confirms these results, with third graders producing a high rate of all types of errors (i.e., phonologically plausible, simple and context-sensitive conversion errors), whereas most errors committed by fifth graders were phonologically plausible. ConclusionsResults are coherent with the hypothesis that dyslexic children learning a shallow orthography suffer from delayed acquisition and some fragility of the sub-word level routine, together with a severe and long-lasting deficit of orthographic lexical acquisition.

Beyond Fast Mapping

Since the seminal 1957 studies of word learning by Roger Brown, most experimental studies of lexical acquisition have concerned fast mapping, that is, the process through which a new lexical entry is established and through which representations of the linguistic context of a newly heard word interact with representations of its nonlinguistic context to fix an initial partial meaning. Here I focus on the subsequent extended process through which the adult meaning is approximated. Two factors lead to an extended learning process: the size of the hypothesis space and the need, sometimes, for the creation of new semantic primitives. Sometimes lexical learning requires conceptual change. I sketch a learning mechanism through which this can be achieved. A case study of learning the meanings of verbal numerals illustrates the argument.

Vocabulário expressivo de crianças com desenvolvimento fonológico normal e desviante

expressive vocabulary of children with normal and deviant phonological development. to determine whether alterations presented by children with phonological disorders occur only at the phonological level or if there are any impacts on lexical acquisition; to compare the vocabulary performance of children with phonological disorders to reference values presented by the used test. participants of the study were 36 children of both genders, 14 with phonological disorders (Study group) and 22 with typical language development (Control Group). The ABFW - Vocabulary Test (Befi-Lopes, 2000) was used for assessing the expressive vocabulary of children and later to compare the performance of both groups. the performance of children with phonological disorder in the expressive vocabulary test is similar to that of children with normal phonological development. Most of the children of both groups reached the benchmarks proposed by the test for the different semantic fields. The semantic field Places demonstrated to be the most complex for both groups. the alterations presented by children with phonological disorder area limited to the phonological level, having no impact on the lexical aspect of language.