This thesis investigates the strategies infants use to generalise labels to different objects in the early stages of lexical development. It aims to directly test the assumption that a taxonomic bias exists which guides infants to extend words to categories of objects instead of individual instances of them, against the hypothesis that infants discover the extension of words through exposure to multiple naming instances of different objects.Experiments One and Two attempted to teach two object-label pairings to infants at the end of their first year of life, and test generalisation of those labels to new objects from the same adult linguistic categories. This aim failed because infants showed evidence for prior knowledge of the words. Experiments Three and Four employed a more infant-controlled procedure using a habituation task during training; in the former a single exemplar from each adult category was used, whereas in the latter multiple exemplars from each category were used. In both Experiments evidence for word learning was provided at test, but infants failed to generalise the labels to other objects. Experiment Five used a training phase identical to Experiment Four but tested infants for perceptual categorisation in the absence of any labels. Some infants showed evidence for their ability to create such categories on the basis of the training set, suggesting that the inability to generalise in Experiments Three and Four was not due to a perceptual limitation. These findings suggest that infants at the end of their first year do not seem to be guided by any linguistic biases in their generalisation of labels. This thesis concludes that 10-month-old infants seem to have more advanced linguistic abilities than has previously been thought and constraint-like behaviour in later stages of lexical development might be a result of experience instead of a qualitative shift in cognitive processes.

Researchers have been reporting temperament-language correlations in infants for 10 years. However, in order to identify directions of effects between temperament and language, methodologies besides correlations need to be developed. The “competition attention paradigm” is an effort to sidestep some of the direction-of-effect issues by asking infants to learn novel words in the context of environmental distractions designed to tap into children’s temperaments. The purpose of the present study was to explore whether environmental distracters would differentially impact 15-month-olds’ novel wordlearning as a function of children’s temperamental profiles. Twenty-eight 15-month-olds were asked to learn 4 novel words. Novel word learning consisted of initially familiarizing children with two novel objects, and then mapping a novel label to only one of the novel objects five times. Novel word comprehension was tested by asking children to select the newly-labeled object from the pair of novel objects across 4 test trials. A remotely-controlled mechanical spider competed for children’s attention during object familiarization on two of the words. Half the children were distracted on the first two words, half were distracted on the last two. Temperament was assessed via parental reporting using the Early Child Behavior Questionnaire. The environmental distractions did not impact children’s word-learning directly. However, order of distraction presentation did [F(1, 23) = 7.16, p = .014], such that children who were distracted on the first two words performed higher overall than children who were distracted on the last two. Results involving temperament were complex, yielding many significant interaction effects with factors impacting children’s word-learning. For example, children high in fear demonstrated better word-learning in the absence of the spider than in its presence, whereas the spider had no effect on low-fear children, but only when learning the first word in the pair [F(1, 23) = 5.20, p = .032]. Other temperament factors found to impact novel word-learning included attentional focus, cuddliness, impulsivity, frustration, and high intensity pleasure. The results of the present investigation contribute to a growing body of research linking temperament to word learning. The competition attention paradigm suggest ways through which word learning may be impacted by dimensions of temperament. Although not presentable here due to space limitations, the pattern of results also points to attentional focus as playing a central moderating role over other dimensions of temperament. Finally, the present results are the first to link temperament to language acquisition at 15 months.

As a group, children with hearing loss show slower language development than their peers with normal hearing. Age of intervention has a profound impact on language outcomes but data examining the correlation between degree of hearing loss and language outcomes are variable. Two approaches are used in the current study to examine this variability. In the first approach, we look at aided speech audibility as a potentially better predictor of communication outcomes than pure tone average. In the second approach, we look at a previously unexplored system in this population: working memory. We enrolled 16 children with mild to moderately-severe hearing loss (CMML) and 24 children with normal hearing (CNH) between 6 and 9 years of age into the study. Over two visits, participants underwent a battery of tests including measures of auditory perception, working memory, word learning, and vocabulary level. Parents completed questionnaires about their child's behavior and executive skills. Our results indicate that our measure of aided speech audibility, the aided Speech Intelligibility Index, was a stronger predictor than pure-tone average, spectral peak resolution, age of identification, age of intervention for word recognition score, nonword repetition score, and receptive vocabulary level. Our results showed little difference between CMML and CNH on measures of working memory including forward and backward digit span and phonological coding bias. We cannot make a strong recommendation for working memory intervention in CMML Reduced audibility causes the most devastating effects on word recognition and vocabulary development. Our results support the recommendation that audibility measures be performed on all children fit with hearing aids and that these measurements be used to flag children who may be at risk for delayed vocabulary acquisition.

The aim of the present study was to investigate whether learning a meaningless phonological word-form, can affect its ability to compete with other words shortly after it was learned. According to previous experimental work we expected that a semantic referent (Leach & Samuel, 2007), and/or consolidation over a significant amount of time (Gaskell& Dumay, 2003) are necessary for a novel word-form to be able to engage in lateral inhibition with other words. In order to examine this we used the experimental design that was used by Dahan, Magnuson, Tanenhaus and Hogan (2001). Experiment 1 was a replication of the Dahan et al (2001) study. In Experiment 2 we added a condition in which a novel word was now assigned the role of the competitor, by inserting a nonword learning task (that was performed right before the Dahan task). The goal was to see whether any differences would arise between this new novel-word condition and the nonword condition. The results from Experiment 2 were inconclusive due to the stimulus set and this is why we conducted Experiment 3, which was similar to Experiment 2, but had a different stimulus set. The results of Experiment 3 showed that, in contrast to the predictions, a novel word can compete with other words, even if it does not have meaning and, moreover, this happens immediately after training. These findings indicate that 1) a word does not have to be complete (i.e. include semantic information) in order to compete with other words and 2) connections between novel and known words can form faster than what has been suggested.

Phonotactic processing is foundational to the word processing task in both monolingual and bilingual children (Li & Farkas, 2002; Pierrehumbert, 2001; Shook & Marian, 2013; Storkel & Morrisette, 2002). While the use of phonotactic information in word processing in monolingual children is relatively well documented, it is less well understood in bilingual children. The purpose of this study was to investigate how bilingual kindergartners process the phonotactic probabilities of their two languages. A set of nonwords was developed that manipulated the strength of phonotactic probability across both Spanish and English while also controlling the language environment of the experimental task (i.e., whether children were tested in Spanish or English). Hence, this study allowed for a unique investigation into how bilingual children process two languages and their associated phonotactic probabilities. Specifically, this study provided answers to: whether or not bilingual children benefitted from a high probability processing advantage, if the phoneme systems of two languages were stored as one unit or separate units, and if there was an effect of language environment (i.e., an assimilation effect, Burki-Cohen et al., 1989). By varying the phonotactic probabilities of nonwords and the language environment), the answers to several research questions were sought. First, language exclusive nonwords (nonwords that had phonotactic probabilities unique to English or Spanish) were used to investigate the presence of a high phonotactic probability processing advantage in bilingual children. Second, high/low nonwords (nonwords with a high phonotactic probability in one language and a low phonotactic probability in the other language) were compared with the language exclusive nonwords to determine if the phonotactic systems of a bilingual child's two languages are stored together such that they interact during word processing. Finally, ambiguous nonwords (those with equal phonotactic probability in both languages) were used to investigate the influence of language environment on phonotactic processing. The nonwords were created by manipulating phonotactic probabilities in each language, recorded by two bilingual speakers, standardized for fundamental frequency and synthesized to become phonetically and acoustically ambiguous. Wordlikeness judgments in each language were obtained from monolingual English and bilingual Spanish-English adults. These results determined that adults were processing the varying phonotactic probabilities of the nonwords as designed and the words were appropriate stimuli for use in a word sorting task with bilingual children. In an attempt to replicate aspects of a natural language environment, the current study first divided children into two bilingual testing groups: one where mostly English was spoken and another where mostly Spanish was spoken. Children watched cartoons illustrating the need for sorting nonwords into two languages before completing the word sorting tasks. The experiment was presented using MouseTracker (Freeman, 2011), which recorded the participant's response and mouse cursor movement (as a measure of decision complexity) as the child selected either Spanish or English. Mixed level modeling results indicated significant differences in language choice but not decision complexity across the nonword types. First, bilingual children sorted language exclusive nonwords by focusing on whether the word was more probable in English or Spanish than whether the nonword had high or low probability within a language. Hence, these participants did not appear to benefit from a high phonotactic processing advantage. When children were sorting the high/low nonwords, they tended to ignore the fact that the nonwords had phonotactic probability in both languages, and treated them as belonging to the language in which they had the highest phonotactic probability. This finding would suggest that bilingual children do not appear to store the phonotactic systems of two languages together. Finally, results showed no effect of language environment when children were sorting the ambiguous nonwords. Overall, it appears that bilingual children focus on the overall phonotactic probability of a nonword (i.e., whether it is more probable in Spanish or English) during processing, while ignoring any dual phonotactic probabilities from two languages. These results are incorporated within a proposed model of bilingual word processing and a brief discussion of how these findings can be expanded to explain bilingual word learning is provided.

One unresolved issue in early word learning research is the relationship between word learning, categorization, and attention. Two distinct cognitive processes, attentional preferences related to categorical processing and inter-modal matching are involved in this relationship. Keeping the effects of these processes separate and controlled can be a difficult task. Not doing so can potentially confound the interpretation of research in this area. In a series of four preferential looking studies, the effects of referential assignment and novelty seeking in infancy were teased apart. In Study 1, 13-month olds preferred to look toward a monitor on which the stimuli changed category on every trial, and away from a monitor on which the stimuli were drawn from a single category. This preference developed in conditions in which infants listened to labels, non-language sound, or participated in silence. In Study 2, 18-month-olds developed the same preference when listening to non-language sounds or when participating in silence, but developed no preference when listening to labels. Results of studies 3 and 4 suggest that the lack of preference by 18-month-olds in the label condition result from competing behaviors of novelty seeking and referential assignment. / text

Previous research has shown that African American children are prone to score lower on vocabulary tests when compared to their white peers (Champion et al., 2003; Qi et al., 2006; Restrepo et al., 2006; Thomas-Tate et al., 2006; Washington & Craig, 1992). The dialect spoken by these children may be affecting their performance. However, little is known about how dialect use interacts with word learning abilities. The current study continues a project initiated by Wyatt, Bahr, and Silliman (2007) which examined dialectal influences on the fast mapping of novel stimuli in preschool children. The participants in the current study were 19 typically developing school-age children, who were recruited from a local elementary school in West Central Florida. Prior to the experiment, the children completed a dialectal variation assessment (DELV) and a receptive vocabulary assessment (PPVT-4). The fast mapping task utilized a modified version of the blank-comparison technique (Costa, Wilkinson, McIlvane, & de Souza, 2001). For this task, twelve non-words were developed to include three AAE phonetic features: final consonant cluster reduction, backing in /str/ clusters, and final consonant devoicing. The non-words were presented in five tasks (training, recognition, comprehension, dialect, and production). Participant responses were analyzed qualitatively and described by dialect group and AAE feature. It was anticipated that fast mapping would be influenced by dialect use; however, this was not the case. Dialect played a small role in the comprehension task -- children who spoke AAE experienced more difficulty with /skr/ non-words. Otherwise, results indicated that responses, especially during the dialect and productions tasks, were similar with numerous errors noted in both dialect groups. A notable difference was in the production of final consonant clusters, where children who spoke AAE evidenced a slight advantage. The lack of a dialect group effect was not surprising since these tasks required the participant to respond to subtle phonetic differences in the target stimuli. As a whole, dialectal influences seemed to be task and feature related. These results will be compared to the previous investigation with preschoolers (Wyatt et al., 2007) and implications for future research will be presented.

Vid flertalet studier har det framkommit att ordförrådets storlek och förmågan till nonordsrepetition påvisar samband med nyordsinlärning. De prosodiska egenskapernas inverkan vid nyordsinlärning är emellertid inte lika studerad. Syftet med föreliggande studie var att undersöka hur barn mellan 4:5 och 6:0 år med typisk språkutveckling presterar på nyordsinlärning i relation till ordförråd och repetition av nonord samt att utforska vilken inverkan prosodiska egenskaper har på förmågan till nyordsinlärning. I studien deltog 15 barn vilkas resultat på nyorden, ordförrådstestningen och nonordsrepetitionen uträknades. Nyordsinlärningsuppgiften bestod av sex ord vilka sammankopplades med sex olika föremål. Nyorden matchades i par med avseende på en åtskiljande prosodisk egenskap mellan dem: antingen antal stavelser, betoning eller ordaccent. Inga signifikanta korrelationer mellan nyordsinlärning, ordförråd och nonordsrepetition kunde påvisas. Det framkom dock att korrelationen mellan ålder och nonordsrepetition var nära signifikans och indikerade att ökad ålder gav ett högre resultat på nonordsrepetitionen. Gällande de prosodiska egenskapernas relation till nyordsinlärning upptäcktes en signifikant skillnad i betoningsplacering, nyord med betoning på den finala stavelsen fick högst resultat. Barnen lärde sig också trestaviga ord i större utsträckning än tvåstaviga ord. Studien implicerar att betoning och ordlängd verkar ha viss betydelse för nyordsinlärning i kontrast till ordaccent, medan det inte kan påvisas några föreliggande korrelationer mellan nyordsinlärning, ordförråd och nonordsrepetition. / Several studies have shown that vocabulary size and nonword repetition ability correlate with novel word learning. The impact of prosodic features on novel word learning has, however, not been studied extensively. The purpose of this study was to examine how children aged 4:5–6:0 with typical language development perform on novel word learning, vocabulary and nonword repetition and to explore what impact prosodic features have on the ability to learn novel words. The study involved 15 children whose performance on the novel word learning task, vocabulary testing and nonword repetition was calculated. The novel word learning task consisted of six words which were connected to six different items. The novel words were matched in pairs differing by only one prosodic feature: either the number of syllables, stress or tonal word accent. No significant correlations between the novel word learning, vocabulary and nonword repetition were found. However, the correlation between age and nonword repetition reached near significance, which indicated that increased age gave a higher result on the nonword repetition. Regarding how the prosodic features related to the novel word learning, a significant difference between stress placements was detected. Novel words with stress on the final syllable were easier to learn. The children also achieved a higher result on the three syllable words than the two syllable words. The study implies that stress and word length seem to play a somewhat important role for novel word learning in contrast to tonal word accent, while it appears to be no relation between novel word learning, vocabulary and nonword repetition.

The cross-situational word learning paradigm argues that word meanings can be approximated by word-object associations, computed from co-occurrence statistics between words and entities in the world. Lexicon acquisition involves simultaneously guessing (1) which objects are being talked about (the ”meaning”) and (2) which words relate to those objects. However, most modeling work focuses on acquiring meanings for isolated words, largely neglecting relationships between words or physical entities, which can play an important role in learning. Semantic parsing, on the other hand, aims to learn a mapping between entire utterances and compositional meaning representations where such relations are central. The focus is the mapping between meaning and words, while utterance meanings are treated as observed quantities. Here, we extend the joint inference problem of word learning to account for compositional meanings by incorporating a semantic parsing model for relating utterances to non-linguistic context. Integrating semantic parsing and word learning permits us to explore the impact of word-word and concept-concept relations. The result is a joint-inference problem inherited from the word learning setting where we must simultaneously learn utterance-level and individual word meanings, only now we also contend with the many possible relationships between concepts in the meaning and words in the sentence. To simplify design, we factorize the model into separate modules, one for each of the world, the meaning, and the words, and merge them into a single synchronous grammar for joint inference. There are three main contributions. First, we introduce a novel word learning model and accompanying semantic parser. Second, we produce a corpus which allows us to demonstrate the importance of structure in word learning. Finally, we also present a number of technical innovations required for implementing such a model.

Bilinguals have the sole option of conversing in one language in spite of knowing two languages. The question of how bilinguals alternate between their two languages, activating and deactivating one language, is not well understood. In the current study, we investigated the development of this process by researching bilingual children's abilities to selectively integrate lexical tone based on its relevance in the language being used. In particular, the current study sought to determine the effects of global conversation-level cues versus local (within-word phonotactic) cues on children's tone integration in newly learned words. Words were taught to children via a conversational narrative, and word recognition was investigated using the intermodal preferential-looking paradigm. Children were tested on recognition of words with stimuli that were either matched or mismatched in tone in both English and Mandarin conversations. Results demonstrated that 3- to 4-year-olds did not adapt their interpretation of lexical tone changes to the language being spoken. In contrast, 4- to 5-year-olds were able to do so when supported by informative within-word cues. Results suggest that preschool children are capable of selectively activating a single language given word-internal cues to language.