Syllable structure and sonority in language inventory and aphasic neologisms

Phonological theories have raised the notion of a universally preferred syllable type which is defined in terms of its sonority structure (e.g., ). Empirical evidence for this notion has been provided by distributional analyses of natural languages and of language acquisition data, and by aphasic speech error analyses. The present study investigates frequency distributions of syllable types in German, which allows for a rather complex syllable structure, and in neologistic utterances of a German speaking jargon aphasic. The findings suggest that the sonority structure of the patient's neologisms is generally in accordance with the notion of theoretically preferred syllables. Moreover, comparative analyses suggest that the predominance of the preferred syllable type is especially pronounced in the aphasic data. On the basis of these findings, the influence of sonority in impaired phonological lexical processing is discussed.     

The role of duration and rapid temporal processing on the lateral perception of consonants and vowels

This study explored the extent to which rapid temporal processing and duration contribute to the right-ear advantage (REA) and presumably left-hemisphere processing for stop consonants and the lack of clear-cut laterality effects for vowels. Three sets of synthetic stimuli were constructed: consonant vowel stimuli [ba da ga bi di gi bu du gu] of 300 msec duration (full stimuli) and two shortened stimuli consisting either of a noise burst and 40-msec transitions (40-msec stimuli), or a noise burst and 20-msec transitions (20-msec stimuli). Stimuli were presented dichotically for consonant, vowel, and syllable identification. Results indicated a significant REA for consonants in the full and 40-msec conditions and a non-significant REA in the 20-msec condition. Nevertheless, the magnitude of laterality did not change across the three conditions. These results suggest that although transition information including duration contributes to lateralization for stop consonants, it is the presence of abrupt onsets which crucially determines lateralized processing. For vowels, there was a significant REA only in the full stimulus condition, and a significant decrement in the magnitude of the laterality effect in the two shortened stimulus conditions. These results suggest that for vowel perception, it is the nature of the acoustic cue used for phonetic identification and not duration that seems to be the critical determinant of lateralization effects.     

Lateralization of speech processing in the brain as indicated by mismatch negativity and dichotic listening

The goal of the present study was to evaluate the differences between dichotic listening and mismatch negativity as measures of speech lateralization in the human brain. For this purpose, we recorded the magnetic equivalent of the mismatch negativity, elicited by consonant-vowel syllable change, and tested the same subjects in the dichotic listening procedure. The results showed that both methods indicated left-hemisphere dominance in speech processing. However, the mismatch negativity, as compared to the right-ear advantage, suggested slightly stronger left-hemisphere dominance in speech processing. No clear correlation was found between the laterality indexes of mismatch negativity and right-ear advantage calculated from dichotic listening results. The possible explanation for this finding would be that these two measures reflect different stages of speech processing in the human brain.     

Tracking independence and merging of prosodic and phonemic processing across infancy

Recent evidence suggests division of labor in phonological analysis underlying speech recognition. Adults and children appear to decompose the speech stream into phoneme‐relevant information and into syllable stress. Here we investigate whether both speech processing streams develop from a common path in infancy, or whether there are two separate streams from early on. We presented stressed and unstressed syllables (spoken primes) followed by initially stressed early learned disyllabic German words (spoken targets). Stress overlap and phoneme overlap between the primes and the initial syllable of the targets varied orthogonally. We tested infants 3, 6 and 9 months after birth. Event‐related potentials (ERPs) revealed stress priming without phoneme priming in the 3‐month‐olds; phoneme priming without stress priming in the 6‐month‐olds; and phoneme priming, stress priming as well as an interaction of both in 9‐month‐olds. In general the present findings reveal that infants start with separate processing streams related to syllable stress and to phoneme‐relevant information; and that they need to learn to merge both aspects of speech processing. In particular the present results suggest (i) that phoneme‐free prosodic processing dominates in early infancy; (ii) that prosody‐free phoneme processing dominates in middle infancy; and (iii) that both types of processing are operating in parallel and can be merged in late infancy.     

Hemispheric specialization for the perception of speech sounds: The influence of intonation and structure

The present report investigates the effect of various cues to phrase structure upon the hemispherically lateralized processing of phonetic structure. Meaningless sequences were paired for dichotic presentation and were delivered under two different conditions termed structured and semistructured. The dichotic sequences in the two conditions contained the same nonsense syllable stems, English bound morphemes, and English function words. Also each of the sequences in both conditions were grammatically ordered in the sense that if the nonsense stems were replaced by English stems, a grammatical sentence would result. The conditions differed with respect to prosody, however: the structured sequences were characterized by the acoustic correlates of constituent structure; the semistructured sequences were delivered in a monotone. A significant right-ear superiority was observed in the structured condition, but not in the semistructured condition. These perceptual laterality differences are discussed in relation to cerebral dominance for language and in relation to speech processing generally.     

Reliability of laterality effects in a dichotic listening task with words and syllables

Large and reliable laterality effects have been found using a dichotic target detection task in a recent experiment using word stimuli pronounced with an emotional component. The present study tested the hypothesis that the magnitude and reliability of the laterality effects would increase with the removal of the emotional component and variations in word frequency. Thirty-two participants completed both a dichotic syllable detection task and a dichotic word detection task. In both tasks, stimuli were pronounced in a neutral tone of voice. Each task was completed twice to allow the estimation of test-retest reliability. Results failed to confirm the hypothesis since they were generally similar to those obtained in the previous study. A significant right ear advantage (REA) was found only with the word task. Although no ear advantage was found for the syllable task, somewhat better reliability was demonstrated compared to that obtained with words. The present findings suggest that including an emotional component does not reduce the reliability or magnitude of auditory laterality effects. In fact, the emotional component may have forced participants to focus on the language aspects of the stimuli. This might partly account for the reduced reliability in words and the absence of REA in syllables. Motivational factors inherent to the within-subject design used here are also discussed.     

Syllabic processing in handwritten word production in German children and adults

Syllables are thought to be processing units in handwritten word production. Yet, little is known about whether the orthographic characteristics of different languages influence syllabic processing during handwriting, which is critical for the evaluation and further development of extant models of handwritten language production. In the present study, we manipulated syllabic ambiguity, a characteristic of the German language, to investigate the role of syllables in handwritten word production in German. Forty-four 10 to 12-year-old children and fourteen adults were asked to write on pen tablets five-letter disyllabic words that varied in terms of their syllabic ambiguity, while their handwriting was recorded with high spatiotemporal resolution. Productions were analyzed in terms of Mean Stroke Duration (MSD) and Writing Onset Duration (WOD). Increased MSD at syllable boundaries was observed across conditions for both children and adults. There was no difference in WOD across conditions. Our findings offer support for the idea that syllables are functional units in handwriting production in German and motivate the further development of the spelling module in models of handwritten language production.     

The valence-specific laterality effect in free viewing conditions: The influence of sex, handedness, and response bias

The right hemisphere has often been viewed as having a dominant role in the processing of emotional information. Other evidence indicates that both hemispheres process emotional information but their involvement is valence specific, with the right hemisphere dealing with negative emotions and the left hemisphere preferentially processing positive emotions. This has been found under both restricted (Reuter-Lorenz & Davidson, 1981) and free viewing conditions (Jansari, Tranel, & Adophs, 2000). It remains unclear whether the valence-specific laterality effect is also sex specific or is influenced by the handedness of participants. To explore this issue we repeated Jansari et al.'s free-viewing laterality task with 78 participants. We found a valence-specific laterality effect in women but not men, with women discriminating negative emotional expressions more accurately when the face was presented on the left-hand side and discriminating positive emotions more accurately when those faces were presented on the right-hand side. These results indicate that under free viewing conditions women are more lateralised for the processing of facial emotion than are men. Handedness did not affect the lateralised processing of facial emotion. Finally, participants demonstrated a response bias on control trials, where facial emotion did not differ between the faces. Participants selected the left-hand side more frequently when they believed the expression was negative and the right-hand side more frequently when they believed the expression was positive. This response bias can cause a spurious valence-specific laterality effect which might have contributed to the conflicting findings within the literature.     

Cross-linguistic differences in the use of durational cues for the segmentation of a novel language

It is widely accepted that duration can be exploited as phonological phrase final lengthening in the segmentation of a novel language, i.e., in extracting discrete constituents from continuous speech. The use of final lengthening for segmentation and its facilitatory effect has been claimed to be universal. However, lengthening in the world languages can also mark lexically stressed syllables. Stress-induced lengthening can potentially be in conflict with right edge phonological phrase boundary lengthening. Thus the processing of durational cues in segmentation can be dependent on the listener’s linguistic background, e.g., on the specific correlates and unmarked location of lexical stress in the native language of the listener. We tested this prediction and found that segmentation by both German and Basque speakers is facilitated when lengthening is aligned with the word final syllable and is not affected by lengthening on either the penultimate or the antepenultimate syllables. Lengthening of the word final syllable, however, does not help Italian and Spanish speakers to segment continuous speech, and lengthening of the antepenultimate syllable impedes their performance. We have also found a facilitatory effect of penultimate lengthening on segmentation by Italians. These results confirm our hypothesis that processing of lengthening cues is not universal, and interpretation of lengthening as a phonological phrase final boundary marker in a novel language of exposure can be overridden by the phonology of lexical stress in the native language of the listener.     

Differential bilingual laterality: mythical monster found in Wales

Paradis (1992) likens studies of bilingual laterality to reported sightings of the Loch Ness Monster, in that although some studies claim differential laterality much conflicting research evidence does not-and like the mythical Scottish monster, what reason have we to suspect that any such phenomenon might exist? This study reexamines differential bilingual laterality using four groups of English-Welsh bilinguals which differ in their age of acquisition and in their environment of acquisition. Using a split visual field paradigm we present evidence which, supports the notion of greater right hemisphere processing in a later learned language. Our findings also suggest the pattern of lateralization in bilinguals is strongly affected by the specific language environment during development such that the shift toward greater right hemisphere involvement for the later learned language will be more pronounced in individuals which are brought up in areas where that language is not regularly heard.     

Neural processing of acoustic duration and phonological German vowel length: Time courses of evoked fields in response to speech and nonspeech signals

Recent experiments showed that the perception of vowel length by German listeners exhibits the characteristics of categorical perception. The present study sought to find the neural activity reflecting categorical vowel length and the short-long boundary by examining the processing of non-contrastive durations and categorical length using MEG. Using disyllabic words with varying /a/-durations and temporally-matched nonspeech stimuli, we found that each syllable elicited an M50/M100-complex. The M50-amplitude to the second syllable varied along the durational continuum, possibly reflecting the mapping of duration onto a rhythm representation. Categorical length was reflected by an additional response elicited when vowel duration exceeded the short-long boundary. This was interpreted to reflect the integration of an additional timing unit for long in contrast to short vowels. Unlike to speech, responses to short nonspeech durations lacked a M100 to the first and M50 to the second syllable, indicating different integration windows for speech and nonspeech signals.     

Laterality briefed: laterality modulates performance in a numerosity-congruity task

It is widely agreed that irrelevant numerical values are automatically activated. However, automatic and intentional activations may give rise to different numerical representations. We examined processing of symbolic and non-symbolic (i.e., numerosity) representations asking whether they differ in automatic and intentional processing. Participants were presented with two-dimensional displays containing repetitions of a digit and were asked to report, in different blocks, whether the digit or numerosity was smaller or larger than 5. Incongruent trials differed either in laterality between the relevant and irrelevant dimensions (i.e., the location of both dimensions in reference to the midpoint 5) or in numerical distance between dimensions. Congruency affected performance regardless of symbolic or non-symbolic presentation. For incongruent trials, laterality (not distance) affected performance, again regardless of presentation. This implies that automaticity does not mean similar processing of relevant and irrelevant dimensions. Specifically, the relevant dimension is processed elaborately whereas the irrelevant dimension is processed crudely.     

Valence specific laterality effects in free viewing conditions: the role of expectancy and gender of image

Recent research has looked at whether the expectancy of an emotion can account for subsequent valence specific laterality effects of prosodic emotion, though no research has examined this effect for facial emotion. In the study here (n=58), we investigated this issue using two tasks; an emotional face perception task and a novel word task that involved categorising positive and negative words. In the face perception task a valence specific laterality effect was found for surprise (positive) and anger (negative) faces in the control but not expectancy condition. Interestingly, lateralisation differed for face gender, revealing a left hemisphere advantage for male faces and a right hemisphere advantage for female faces. In the word task, an affective priming effect was found, with higher accuracy when valence of picture prime and word target were congruent. Target words were also responded to faster when presented to the LVF versus RVF in the expectancy but not control condition. These findings suggest that expecting an emotion influences laterality processing but that this differs in terms of the perceptual/experience dimension of the task. Further, that hemispheric processing of emotional expressions appear to differ in the gender of the image.     

Laterality in metaphor processing: lack of evidence from functional magnetic resonance imaging for the right hemisphere theory

We investigated processing of metaphoric sentences using event-related functional magnetic resonance imaging (fMRI). Seventeen healthy subjects (6 female, 11 male) read 60 novel short German sentence pairs with either metaphoric or literal meaning and performed two different tasks: judging the metaphoric content and judging whether the sentence has a positive or negative connotation. Laterality indices for 8 regions of interest were calculated: Inferior frontal gyrus (opercular part and triangular part), superior, middle, and inferior temporal gyrus, precuneus, temporal pole, and hippocampus. A left lateralised network was activated with no significant differences in laterality between the two tasks. The lowest degree of laterality was found in the temporal pole. Other factors than metaphoricity per se might trigger right hemisphere recruitment. Results are discussed in the context of lesion and hemifield studies.     

Associated or dissociated effects of syllable frequency in lexical decision and naming

Most empirical work investigating the role of syllable frequency in visual word recognition has focused on the Spanish language, in which syllable frequency seems to produce a classic dissociation: inhibition in lexical decision tasks but facilitation in naming. In the present study, two experiments were run in German, using identical stimulus materials, in a lexical decision task and a naming task. In both tasks, there was an inhibitory effect for words with a high-frequency first syllable. This pattern of results, suggesting a stronger weight of lexical access in the naming process in German than in Spanish, is discussed with regard to the issue of stress assignment in the two languages and within the framework of word production models. Items, mean response latencies, and accuracy rates per item for both experiments can be downloaded from www.psychonomic.org/archive.     

Syllables as units in speech production: Data from aphasia

The syllable has received considerable empirical support as a unit of processing in speech perception, but its status in speech production remains unclear. Some researchers propose that syllables are individually represented and retrieved during phonological encoding (e.g., Dell, 1986; Ferrand, Segui, & Grainger, 1996; MacKay, 1987). We test this hypothesis by examining the influence of syllable frequency on the phonological errors of two aphasics. These individuals both had an impairment in phonological encoding, but appeared to differ in the precise locus of that impairment. They each read aloud and repeated 110 pairs of words matched for syllabic complexity, but differing in final syllable frequency. Lexical frequency was also controlled. Neither aphasic was more error-prone on low than on high frequency syllables (indeed, one showed a near-significant reverse effect), and neither showed a preference for more frequent syllables in their errors. These findings provide no support for the view that syllables are individually represented and accessed during phonological encoding.     

Valence specific laterality effects in free viewing conditions: The role of expectancy and gender of image

Recent research has looked at whether the expectancy of an emotion can account for subsequent valence specific laterality effects of prosodic emotion, though no research has examined this effect for facial emotion. In the study here (n = 58), we investigated this issue using two tasks; an emotional face perception task and a novel word task that involved categorising positive and negative words. In the face perception task a valence specific laterality effect was found for surprise (positive) and anger (negative) faces in the control but not expectancy condition. Interestingly, lateralisation differed for face gender, revealing a left hemisphere advantage for male faces and a right hemisphere advantage for female faces. In the word task, an affective priming effect was found, with higher accuracy when valence of picture prime and word target were congruent. Target words were also responded to faster when presented to the LVF versus RVF in the expectancy but not control condition.These findings suggest that expecting an emotion influences laterality processing but that this differs in terms of the perceptual/experience dimension of the task. Further, that hemispheric processing of emotional expressions appear to differ in the gender of the image.     

Reading rates of stutterers and nonstutterers during silent and oral reading

The purpose of this study was to investigate the differences between the reading rates of stutterers and nonstutterers during both silent and oral reading of fluently spoken words. Ten adult stutterers and 14 nonstutterers were instructed to read two lists of words over four trials each. The first trial of either the first or the second list was a silent reading trial. All the other trials were oral reading trials. The word lists consisted of nouns with word lengths from two to five syllables. The dependent variables were the silent and oral reading times per word and per syllable. The major findings were that stutterers, as compared to nonstutterers, required longer reading times per word and per syllable during both silent and oral reading. These results indicate that stutterers differ from nonstutterers in the basic processing time for verbal material.     

The role of syllables in word recognition among beginning Finnish readers: Evidence from eye movements during reading

The eye movements of Finnish first and second graders were monitored as they read sentences where polysyllabic words were either hyphenated at syllable boundaries, alternatingly coloured (every second syllable black, every second red) or had no explicit syllable boundary cues (e.g., ta-lo vs. talo vs. talo = “house”). The results showed that hyphenation at syllable boundaries slows down reading of first and second graders even though syllabification by hyphens is very common in Finnish reading instruction, as all first-grade textbooks include hyphens at syllable boundaries. When hyphens were positioned within a syllable (t-alo vs. ta-lo), beginning readers were even more disrupted. Alternate colouring did not affect reading speed, no matter whether colours signalled syllable structure or not. The results show that beginning Finnish readers prefer to process polysyllabic words via syllables rather than letter by letter. At the same time they imply that hyphenation encourages sequential syllable processing, which slows down the reading of children, who are already capable of parallel syllable processing or recognising words directly via the whole-word route.     

The laterality effect: myth or truth?

Tzelgov and colleagues [Tzelgov, J., Meyer, J., and Henik, A. (1992). Automatic and intentional processing of numerical information. Journal of Experimental Psychology: Learning, Memory and Cognition, 18, 166-179.], offered the existence of the laterality effect as a post-hoc explanation for their results. According to this effect, numbers are classified automatically as small/large versus a standard point under autonomous processing of numerical information. However, the genuinity of the laterality effect was never examined, or was confounded with the numerical distance effect. In the current study, I controlled the numerical distance effect and observed that the laterality effect does exist, and affects the processing of automatic numerical information. The current results suggest that the laterality effect should be taken into account when using paradigms that require automatic numerical processing such as Stroop-like or priming tasks.