Laterality effects in the processing of syllable structure.

Recent phonological research has shown that the syllable plays a major role in the phonology of German. The present study investigates laterality effects in the processing of syllable structure by means of dichotic presentation of German word pairs that differ in number of syllables, but that differ minimally in the phonemes they comprise (e.g., BREIT and BEREIT). Results showed a sex difference in laterality for the processing of the experimental stimuli, with a greater right-hemispheric lateralization in men and a more bilateral organization in women.     

Explicit syllable and phoneme segmentation in the young child

To write a language, one must first abstract the unit to be used from the acoustic stream of speech. Writing systems based on the meaningless units, syllables and phonemes, were late developments in the history of written language. The alphabetic system, which requires abstraction of the phonemic unit of speech, was the last to appear, evolved from a syllabary and, unlike the other systems, was apparently invented only once. It might therefore be supposed that phoneme segmentation is particularly difficult and more difficult, indeed, than syllable segmentation. Speech research suggests reasons why this may be so. The present study provides direct evidence of a similar developmental ordering of syllable and phoneme segmentation abilities in the young child. By means of a task which required preschool, kindergarten, and first-grade children to tap out the number of segments in spoken utterances, it was found that, though ability in both syllable and phoneme segmentation increased with grade level, analysis into phonemes was significantly harder and perfected later than analysis into syllables. The relative difficulties of the different units of segmentation are discussed in relation to reading acquisition.     

Extralinguistic control of language comprehension and production in the nonfluent child

The study investigated (1) the developmental progression postulated to exist between comprehension and production of sentences having the same grammatical form, and (2) the effects of syntactic, semantic, and extralinguistic variables on comprehension and production in nursery-school children. Comprehension trials required choices among four puzzle piece alternatives for which (a) both subject and object pieces differed (Phase I) or (b) only grammatical subject pictures differed (Phase II). During production trials children were asked to label preconstructed puzzles. Results indicated the comprehension-production relationship to vary as a function of age, sentence prepositions, and phases. Differential effects of semantic and extralinguistic variables during comprehension were found primarily for the youngest children, suggesting that logical relations among agent-actor-object were not sole controllers of language comprehension. Nonsyntactic control of production responses was not found.     

Effects of syllable structure in aphasic errors: implications for a new model of speech production

Current models of word production assume that words are stored as linear sequences of phonemes which are structured into syllables only at the moment of production. This is because syllable structure is always recoverable from the sequence of phonemes. In contrast, we present theoretical and empirical evidence that syllable structure is lexically represented. Storing syllable structure would have the advantage of making representations more stable and resistant to damage. On the other hand, re-syllabifications affect only a minimal part of phonological representations and occur only in some languages and depending on speech register. Evidence for these claims comes from analyses of aphasic errors which not only respect phonotactic constraints, but also avoid transformations which move the syllabic structure of the word further away from the original structure, even when equating for segmental complexity. This is true across tasks, types of errors, and, crucially, types of patients. The same syllabic effects are shown by apraxic patients and by phonological patients who have more central difficulties in retrieving phonological representations. If syllable structure was only computed after phoneme retrieval, it would have no way to influence the errors of phonological patients. Our results have implications for psycholinguistic and computational models of language as well as for clinical and educational practices.     

Relative salience of syllable structure and syllable order in zebra finch song

There is a rich history of behavioral and neurobiological research focused on the ‘syntax’ of birdsong as a model for human language and complex auditory perception. Zebra finches are one of the most widely studied songbird species in this area of investigation. As they produce song syllables in a fixed sequence, it is reasonable to assume that adult zebra finches are also sensitive to the order of syllables within their song; however, results from electrophysiological and behavioral studies provide somewhat mixed evidence on exactly how sensitive zebra finches are to syllable order as compared, say, to syllable structure. Here, we investigate how well adult zebra finches can discriminate changes in syllable order relative to changes in syllable structure in their natural song motifs. In addition, we identify a possible role for experience in enhancing sensitivity to syllable order. We found that both male and female adult zebra finches are surprisingly poor at discriminating changes to the order of syllables within their species-specific song motifs, but are extraordinarily good at discriminating changes to syllable structure (i.e., reversals) in specific syllables. Direct experience or familiarity with a song, either using the bird’s own song (BOS) or the song of a flock mate as the test stimulus, improved both male and female zebra finches’ sensitivity to syllable order. However, even with experience, birds remained much more sensitive to structural changes in syllables. These results help to clarify some of the ambiguities from the literature on the discriminability of changes in syllable order in zebra finches, provide potential insight on the ethological significance of zebra finch song features, and suggest new avenues of investigation in using zebra finches as animal models for sequential sound processing.     

Effects of syllable frequency in speech production

In the speech production model proposed by [Levelt, W. J. M., Roelofs, A., Meyer, A. S. (1999). A theory of lexical access in speech production. Behavioral and Brain Sciences, 22, pp. 1-75.], syllables play a crucial role at the interface of phonological and phonetic encoding. At this interface, abstract phonological syllables are translated into phonetic syllables. It is assumed that this translation process is mediated by a so-called Mental Syllabary. Rather than constructing the motor programs for each syllable on-line, the mental syllabary is hypothesized to provide pre-compiled gestural scores for the articulators. In order to find evidence for such a repository, we investigated syllable-frequency effects: If the mental syllabary consists of retrievable representations corresponding to syllables, then the retrieval process should be sensitive to frequency differences. In a series of experiments using a symbol-position association learning task, we tested whether high-frequency syllables are retrieved and produced faster compared to low-frequency syllables. We found significant syllable frequency effects with monosyllabic pseudo-words and disyllabic pseudo-words in which the first syllable bore the frequency manipulation; no effect was found when the frequency manipulation was on the second syllable. The implications of these results for the theory of word form encoding at the interface of phonological and phonetic encoding; especially with respect to the access mechanisms to the mental syllabary in the speech production model by (Levelt et al.) are discussed.     

A pragmatic perspective of repetition in child language

The contention that repetition may be used for a variety of communicative functions is supported with data from a longitudinal study of one child. Repetitions were identified from videotapes and then classified according to the communicative function being expressed. Additionally, discourse profiles were identified for various communicative functions being expressed via repetition.     

A neuronal model for syllable representation

A speculative neuronal template, equivalent to canonical syllable forms and independent of segmental representations, is offered to help account for (1) the inviolate nature of phonotactic constraints in aphasic speech output, and (2) left hemisphere specialization for speech sound access and output. The model, which attempts to relate plausible neuronal systems to linguistic function, is based on cell assemblies that are thought to develop by way of genetic predisposition and ontogenetic language experience, into configurations that can represent canonical slot positions for the consonants and vowel comprising a syllable. The syllable is assumed to be the basic organizational rhythmic unit for serial concatenation of sublexical segments. A scheme for neurological differentiation of vowels and consonants is offered. Phonotactic constraints can become "hard-wired" to help create the automaticity underlying phonological sound organization. Testable predictions are offered to substantiate the claims of the model.     

A method for examining gestural language structure

This experiment tested the hypothesis that syntactic constituents in American Sign Language (ASL) serve as perceptual units. We adapted the strategy first employed by Fodor and Bever in 1965 in a study of the psychological reality of linguistic speech segments. Four deaf subjects were shown ASL sign sequences constructed to contain a single constituent break. The dependent measure was the subjective location of a light flash occurring during the sign sequence. The prediction that the flashes would be attracted to the constituent boundary was supported for two of the subjects, while the other two showed random placement of the flash location on either side of the constituent boundary. The two subjects not performing in the predicted direction were more proficient in English (written) than the two giving the effect. It was suggested that this relatively greater proficiency may have interfered in some way with the ASL syntax to produce the results obtained.     

Syllable frequency and syllable structure in apraxia of speech

Recent accounts of the pathomechanism underlying apraxia of speech (AOS) were based on the speech production model of Levelt, Roelofs, and Meyer, and Meyer (1999)1999. The apraxic impairment was localized to the phonetic encoding level where the model postulates a mental store of motor programs for high-frequency syllables. Varley and Whiteside (2001a) assumed that in patients with AOS syllabic motor programs are no longer accessible and that these patients are required to use a subsyllabic encoding route. In this study, we tested this hypothesis by exploring the influence of syllable frequency and syllable structure on word repetition in 10 patients with AOS. A significant effect of syllable frequency on error rates was found. Moreover, apraxic errors on consonant clusters were influenced by their position relative to syllable boundaries. These results demonstrate that apraxic patients have access to the syllabary, but that they fail to retrieve the syllabic motor patterns correctly. Our findings are incompatible with a subsyllabic route model of apraxia of speech.     

A developmental deficit in short-term phonological memory: Implications for language and reading

Abstract

QU, an eight-year-old boy, was identified from a large scale normative study on the basis of his greatly reduced digit span, combined with normal long-term memory and non-verbal intelligence. Further investigation indicated that his visual STM was normal, but that he was clearly impaired on two verbal STM tests, nonword repetition, and memory span for words. His span showed clear effects of phonological similarity and word-length, suggesting qualitatively normal functioning of the phonological loop component of working memory, despite a quantitative impairment in level of performance. This pattern resembles that found in an earlier study of children with a specific language disorder. We tested QU on measures of vocabulary, syntax, and reading, and found him to be substantially below the age norms on all three. The implications of these findings are discussed for the role of the phonological loop in language development.     

Subgroups of developmental language impairment

Nineteen children with developmental language impairments were given tests which measured syntactic and phonological skills in both comprehension and production conditions, semantic ability, syllable sequencing, and digit span. The results of discriminant function analysis show that the children could be divided into two groups. Group 1, expressive, was characterized primarily by deficits in the production of syntax and phonology. Group 2, expressive-receptive, was more impaired on measures of phonological discrimination, digit span, and semantic ability in addition to showing global syntactic deficits. An auditory-perceptual basis for the language impairments was not supported.     

Neural modeling and imaging of the cortical interactions underlying syllable production

This paper describes a neural model of speech acquisition and production that accounts for a wide range of acoustic, kinematic, and neuroimaging data concerning the control of speech movements. The model is a neural network whose components correspond to regions of the cerebral cortex and cerebellum, including premotor, motor, auditory, and somatosensory cortical areas. Computer simulations of the model verify its ability to account for compensation to lip and jaw perturbations during speech. Specific anatomical locations of the model's components are estimated, and these estimates are used to simulate fMRI experiments of simple syllable production.     

Asynchronous language acquisition in developmental dysphasia

A longitudinal study was conducted to document and compare evolution of children with linguistic acquisition impairment. To determine whether development of the analytic mechanisms underlying linguistic processing occured in similar fashion, two children with mixed developmental dysphasia were assessed from 4 to 5:6 years of age with psycholinguistic tests at 6-months interval. Spontaneous speech and language production (consonant repertory in initial word position, MLU, and lexical diversity) were investigated in a standardized symbolic play context. The phonologic and lexico-morphologic evolution analyses revealed a marked improvement in motor control of phonology and in the application of morphosyntaxic rules in child 1, whereas child 2 was still impaired in phonology and morphosyntax. The singular developmental changes in spontaneous speech results indicate dynamic relationships between various language production facets and variability in the kind of deficit and lexical automation presented by these children. These contrasts in the evolution of language production profiles between child 1 and child 2 also underline the importance of longitudinal studies in the analysis of the atypical linguistic processing paths used by children with developmental dysphasia.     

Verb reading in developmental language impairment

This research addresses the issues of frequency and regularity in verb reading and their importance for the organization of the mental lexicon in DLI francophones. A reading task probes response latencies and response accuracy for DLI and control participants on frequent and infrequent inflected forms of verbs. DLI participants are slower at reading verbs even if their mean accuracy rates are higher than controls'. Results also indicate that the type of suffix on the verb affects controls and DLI participants differently in their accuracy rates: DLI participants exhibit higher error rates on less frequent inflections, while controls do not. Finally, unusual patterns are found for DLI participants on regular versus irregular verbs: regular verbs are slower to be read by DLI participants. These results are compared to findings from a previous simple lexical decision study. They are interpreted as indicating that DLI word reading patterns are qualitatively different from those evidenced by controls.     

Stages of lexical access in language production.

We describe two primary stages in the top-down process of lexical access in production, a stage of lemma access in which words are retrieved as syntactic-semantic entities, and a stage of phonological access in which the forms of the words are fleshed out. We suggest a reconciliation of modular and interactive accounts of these stages whereby modularity is traceable to the action of discrete linguistic rule systems, but interaction arises in the lexical network on which these rules operate. We also discuss the time-course of lexical access in multi-word utterances. We report some initial production priming explorations that support the hypothesis that lemmas are buffered in longer utterances before they are phonologically specified. Because such techniques provide a relatively direct way of assessing activation at the primary stages of lexical access they are an important new resource for the study of language production.     

On the psychological reality of a natural rule of syllable structure

If natural rules in phonology, such as the rule which deletes a word final consonant before a consonant, are frequently found in unrelated languages, it must be because they tap universal features of production and/or perception. The present experiment employed a learning task to see whether naive subjects have a predisposition for the natural rule as opposed to its converse (consonant deletion before a vowel). The Ss first learned four novel words (nouns) - two beginning with a consonant, two with a vowel - as paired associates to English ‘translations’. Then three novel adjectives were combined with each of the four nouns, following the natural rule for one group of Ss, the unnatural rule for the other. The twelve phrases were cued by their English translations and the S had to respond to each with the phonologically correct sequence of adjective and noun; confirmation followed each response. The Ss learning the unnatural corpus had a strong tendency to give natural responses, whereas the converse was not true. Consequently they made many more errors en route to mastery than their natural counterparts, even when the operative rule was displayed on the first trial by presenting in turn each adjective with its four following nouns. It appears that our Ss had implicit knowledge of the natural rule, even though it does not operate to any significant extent in English.     

Auditory verb recognition in developmental language impairment

This research addresses the issues of frequency and regularity in auditory verb recognition and their importance for the organization of the mental lexicon in DLI francophones. A primed auditory lexical decision task probes reaction times and response accuracy in DLI and control participants on frequent and infrequent, and regular and irregular, inflected forms of verbs. Results show no priming for inflectionally related forms as well as strong frequency effects in DLI participants. These findings lend additional support to the hypothesis that developmental language impairment is a deficit in lexical representation.