Many theorists have dismissed a priori the idea that distributional information could play a significant role in syntactic category acquisition. We demonstrate empirically that such information provides a powerful cue to syntactic category membership, which can be exploited by a variety of simple, psychologically plausible mechanisms. We present a range of results using a large corpus of child-directed speech and explore their psychological implications. While our results show that a considerable amount of information concerning the syntac-tic categories can be obtained from distributional information alone, we stress that many other sources of information may also be potential contributors to the identification of syntactic classes. I.

The psychological reality of English phonaesthemes is demonstrated through a priming experiment with native speakers of American English. Phonaesthemes are well-represented soundmeaning pairings, such as English gl-, which occurs in numerous words with meanings relating to light and vision. In the experiment, phonaesthemes, despite being noncompositional in nature, displayed priming effects much like those that have been reported for compositional morphemes. These effects could not be explained as the result of semantic or phonological priming, either alone or in combination. The results support a view of the lexicon in which shared form and meaning across words is a key factor in their relatedness, and in which morphological composition is not required for internal word structure to play a role in language processing.* 1. INTRODUCTION. Phonaesthemes (Firth 1930) are frequently recurring soundmeaning pairings that are not clearly contrastive morphemes. An example is the English onset gl- (Wallis 1699, Bloomfield 1933), which, like otherphonaesthemes, is relatively infrequent in English, except among words with meanings related to ‘vision ’ and ‘light’. Some of these are exemplified in 1a. Another well-documented phonaestheme (Wallis

Languages are felt to be spoken with different kinds of rhythm. Traditional accounts have proposed that some languages are "stress-timed", while others are "syllable-timed". Despite the intuitive appeal of this typology, however, there is little phonetic evidence for the distinction. Meanwhile, generative phonology fails to provide clear explications on how formal representations of linguistic rhythm are to be phonetically interpreted. This thesis compared the rhythmic organization of English and Japanese using a novel experimental method, called "speech cycling", in which subjects produce a given phrase repeatedly in time with a controlled metronome. The task induces overtly rhythmic forms of speaking, and overcomes difficulties encountered by earlier studies in finding reliable physical correlates of speech rhythm and its variation across languages. In Experiment 1, subjects were asked to repeat phrases at a continuum of speaking rates, in order to examine whether they would fall in ...

Recent work in developmental psycholinguistics suggests that children may bootstrap grammatical categories and basic syntactic structure by exploiting distributional, phonological, and prosodic cues. Previous connectionist work has indicated that multiple-cue integration is computationally feasible for small artificial languages. In this paper, we present a series of simulations exploring the integration of distributional and phonological cues in a connectionist model trained on a fullblown corpus of child-directed speech. In the first simulation, we demonstrate that the connectionist model performs very well when trained on purely distributional information represented in terms of lexical categories. In the second simulation we demonstrate that networks trained on distributed vectors incorporating phonetic information about words also achieve a high level of performance. Finally, we employ discriminant analyses of hidden unit activations to show that the networks are able to integrate phonological and distributional cues in the service of developing highly reliable internal representations of lexical categories.

Before children can ride a bicycle or tie their shoes, they have learned a great deal about how words are combined to form complex sentences. This achievement is especially impressive because children acquire most of this syntactic knowledge with little or no direct instruction. Nevertheless, mastering natural language syntax may be among the most difficult learning tasks

Traditional linguistic models are categorical. Recently, though, a number of researchers have begun to study non-categorical human linguistic knowledge (e.g. Bender 2000, Pierrehumbert 2000, Frisch 2001). This new empirical focus has posed significant difficulties for categorical models, which cannot account for many non-categorical phenomena. Rather than trying to fit the non-categorical complexities of language into categorical models, a number of researchers have begun to treat non-categoriality in probabilistic terms (Jurafsky 1996, Abney 1996, Bod 1998). This dissertation demonstrates experimentally that language users have knowledge of non-categorical correlations between phonology and other grammatical, semantic, and social knowledge and that they apply this knowledge to the task of language perception. The thesis also proposes neural explanations for the behavior exhibited in the experiments, and develops neurally plausible, probabilistic computational models to this end. This first half of this dissertation presents new evidence of the non-categoriality of human linguistic knowledge through two case studies. The first addresses the relation between sound and meaning, though an experimental investigation of the psychological reality of English phonaesthemes, and shows that these non-categorical sub-morphemic sound-meaning pairings are psychologically real. A second, larger study addresses the multiple factors that non-categorically affect a particular morpho-phonological process in French, called liaison. These two studies provide evidence that language users access noncategorical relations between phonological patterns and their phonological, morphological, syntactic, semantic, and social correlates. An additional result of the liaison study is the finding that language users exhibit unconscious knowledge of non-categorical interactions between factors that influence this morpho-phonological process. While there are general neural explanations for the ability to learn and represent the knowledge suggested by these studies, a formal model can only be produced in a computational architecture. Therefore, in the dissertation's second half, I develop a computational model of non-categorical, cross-modal knowledge using a probabilistic architecture used in Artificial Intelligence research, known as Belief Networks (Pearl 1988). In addition to capturing the generalizations about non-categorical knowledge evidenced by the two case studies, Belief Networks are neurally plausible, making them a sound architecture for a bridging model between neural structure and cognitive and linguistic behavior.

We present a psycholinguistic experiment that investigates the influence of conceptual accessibility on word order in Modern Greek. Previous claims about the effects of conceptual accessibility on language production reported effects on grammatical function assignment only, detecting a preference for more conceptually accessible entities to be assigned to more prominent grammatical roles (such as subject). Researchers concluded that conceptual accessibility affected word order only indirectly. However, in English grammatical function and word order are tightly connected, and as a consequence a change in grammatical function results also in a different syntactic construction. Modern Greek, on the other hand, is a free word order language and was chosen because it allows differentiation between effects which are due to grammatical function, and effects which are due to word order. Our experiment shows that conceptual accessibility has an effect on word order, yet the effects on grammatic...

We propose an explicit, incremental strategy by which children could group words with similar syntactic privileges into discrete, unlabeled categories. This strategy, which can discover lexical ambiguity, is based in part on a generalization of the idea of sentential minimal pairs. As a result, it makes minimal assumptions about the availability of syntactic knowledge at the onset of categorization. Although the proposed strategy is distributional, it can make use of categorization cues from other domains, including semantics and phonology. Computer simulations show that this strategy is effective at categorizing words in both artificial-language samples and transcripts of naturally-occurring, child-directed speech. Further, the simulations show that the proposed strategy performs even better when supplied with semantic information about concrete nouns. Implications for theories of categorization are discussed.

Certain types of speech, e.g. lists of words or numbers, are usually spoken with a clear speech rhythm. Salient, stressed vowels are aligned to rhythmic points within the phrase period. The main hypothesis of this study (derived from the Dynamic Attending Theory; M.R. Jones (1976), Psych. Rev. 83, 323--355) is that listeners attend in particular to speech events at these rhythmic time points. Better rhythmic regularity should improve spoken-word perception. Previous studies that suggested only a weak effect of speech rhythm on spoken-word perception, suffered from poor control over speech rhythm in their stimuli. A phoneme monitoring experiment is reported, in which listeners heard lists of disyllabic words in which the rhythm of the stressed vowels was either regular (with equidistant inter-stress intervals) or jittery. In addition, metrical expectancy was controlled by varying the stress pattern of the target word, as either the same or the opposite of the stress pattern in its preceding words. Resulting RTs show a main effect of rhythmic regularity, but not of metrical expectancy. Rhythmic regularity had its strongest effect in the perception of iambic words. These results suggest that listeners employ attentional rhythms in spoken-word perception, and that a clear rhythm improves speech communication.