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Evidence from electrophysiological measures such as ERPs (event-related potentials) and MEG (magnetoencephalography) suggest that the first evoked brain response component sensitive to stimulus properties affecting reaction times in word recognition tasks occurs at 300-400 ms. The present study used the stimulus manipulation of Vitevich and Luce (1999) to investigate whether the M350, an MEG response component peaking at 300400 ms, reflects lexical or post-lexical processing. Stimuli were simultaneously varied in phonotactic probability, which facilitates lexical activation, and in phonological neighborhood density, which inhibits the lexical decision process. The present results indicate that the M350 shows facilitation by phonotactic probability rather than inhibition by neighborhood density. Thus the M350 cannot be a post-lexical component. (118 words) Keywords: MEG, lexical decision, lexical access, phonotactic probability, neighborhood effects, N400, M350 3

Most words in natural language are polysemous, that is, they can be used in more than one way. For example, paper can be used to refer to a substance made out of wood pulp or to a daily publication printed on that substance. Although virtually every sentence contains polysemy, there is little agreement as to how polysemy is represented in the mental lexicon. Do different uses of polysemous words involve access to a single representation or do our minds store distinct representations for each different sense? Here we investigated priming between senses with a combination of behavioral and magnetoencephalographic measures in order to test whether different senses of the same word involve identity or mere formal and semantic similarity. Our results show that polysemy effects are clearly distinct from similarity effects bilaterally. In the left hemisphere, sense-relatedness elicited shorter latencies of the M350 source, which has been hypothesized to index lexical activation. Concurrent activity in the right hemisphere, on the other hand, peaked later for sense-related than for unrelated target stimuli, suggesting competition between related senses. The obtained pattern of results supports models in which the representation of polysemy involves both representational identity and difference: Related senses connect to same abstract lexical representation, but are distinctly listed within that representation.

co-occurrence restrictions Ethiopian Semitic similarity speech errors This article reports the results of speech error elicitation experiments investigating the role of two consonant co-occurrence restrictions in the productive grammar of speakers of two Ethiopian Semitic languages, Amharic and Chaha. Higher error rates were found with consonant combinations that violated co-occurrence constraints than with those that had only a high degree of shared phonological similarity or low frequency of co-occurrence. Sequences that violated two constraints had the highest error rates. The results indicate that violations of consonant co-occurrence restrictions significantly increase error rates in the productions of native speakers, thereby supporting the psychological reality of the constraints. 1

A growing body of evidence on adult phonological processing supports the idea that phonological knowledge emerges through generalization over the experience of acquiring and using words. Some of this evidence suggests that knowledge is hierarchical, with generalization occurring at several different levels of abstraction away from the raw sensory input. Each familiar word-form has a distributed representation in the parametric phonetic space, which captures relevant generalizations over an individual’s experience of hearing and saying specific tokens of the same word, but a parallel coarser-grained representation can be composed on the fly to process novel forms in terms of generalizations over the neighborhood of different word-forms in the individual’s mental lexicon. Results of several studies of two clinical populations suggest that these different types of phonological knowledge can develop separately. Children with phonological disorder resemble younger children with typical phonological development in terms of measures of the robustness of parametric phonetic representations, whereas children with specific language impairment look like children with smaller vocabularies in terms of their processing of nonwords. 1.

The psychological reality of an abstract consonant dissimilation constraint is demonstrated in an experiment with native speakers of Jordanian Arabic. In this experiment, novel verbs containing constraint violations and those without violations were presented orthographically for judgments of well-formedness. Native speaker well-formedness judgments reflected knowledge of the phonotactic constraint. Systematic gaps were rated much less wordlike than accidental gaps that were equivalent in their lexical characteristics. Judgments for novel verbs containing constraint violations were also gradiently influenced by consonant pair similarity. The experimental study supports previous dictionary-based phonotactic analyses that propose that the native speaker’s knowledge of consonant cooccurrence constraints in Arabic is based on emergent generalizations over the lexical items in an abstract root lexicon.* The phonotactic constraints of a language define the set of possible words in that language. Typically, phonotactic constraints are restrictions on the possible consonant clusters in a language or conditions on the minimal prosodic unit that can be considered a word. Such constraints undoubtedly have an impact on productive word formation and foreign word accommodation, and thus these constraints are assumed to be active

The effects of lexical context on phonological processing are pervasive and there have been indications that such effects may be modulated by attention. However, attentional modulation in speech processing is neither well-documented nor well-understood. Experiment 1 demonstrated attentional modulation of lexical facilitation of speech sound recognition when task and critical stimuli were identical across attention conditions. We propose modulation of lexical activation as a neurophysiologically-plausible computational mechanism that can account for this type of modulation. Contrary to the claims of critics, this mechanism can account for attentional modulation without violating the principle of interactive processing. Simulations of the interactive TRACE model extended to include two different ways of modulating lexical activation showed that each can account for attentional modulation of lexical feedback effects. Experiment 2 tested conflicting predictions from the two implementations and provided evidence that is consistent with bias input as the mechanism of attentional control of lexical activation.

Phonological grammars characterize distinctions between relatively well-formed (unmarked) and relatively ill-formed (marked) phonological structures. We review evidence that markedness influences speech error probabilities. Specifically, although errors result in both unmarked as well as marked structures, there is a markedness asymmetry: errors are more likely to produce unmarked outcomes. We show that stochastic disruption to the computational mechanisms realizing a Harmonic Grammar (HG) can account for the broad empirical patterns of speech errors. We demonstrate that our proposal can account for the general markedness asymmetry. We also develop methods for linking particular HG proposals to speech error distributions, and illustrate these methods using a simple HG and a set of initial consonant errors in English. 1. Phonological markedness and linguistic behavior * A central concern of generative phonological theory is to characterize the relative well-formedness of phonological structures. In this paper we will use the term markedness to refer to distinctions in well-formedness (where well-formed structures are

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