Listener preferences for stuttered and syllable-timed speech production

The purpose of this study was to determine how “naive” listeners react to syllable-timed speech production. Three stutterers were videotape recorded while speaking in their usual manner and pacing their speech at 100 words per minute (wpm) and 70 wpm. Twenty-three listeners rated the speech samples as to which they preferred to hear. The results indicated generally that listeners preferred paced speech to stuttering.     

Music draws attention to the left and speech draws attention to the right

Providing free-field music input prompts right-handers to attend to their left side in a loudness-matching task that requires no musical analysis. Conversely, speech prompts rightward attention. The processes inferred are akin to the attentional asymmetry demonstrated in the syndrome of hemispatial neglect.     

An analysis of speech perception in word deafness

A patient with a rather pure word deafness showed extreme suppression of right ear signals under dichotic conditions, suggesting that speech signals were being processed in the right hemisphere. Systematic errors in the identification and discrimination of natural and synthetic stop consonants further indicated that speech sounds were not being processed in the normal manner. Auditory comprehension improved considerably however, when the range of speech stimuli was limited by contextual constraints. Possible implications for the mechanism of word deafness are discussed.     

The speech production abilities of stutterers: Recent, ongoing, and future research

Recent and ongoing research into the speech production abilities of stutterers has followed four disparate paths. First, there have been objective studies of physiologic, aerodynamic, and acoustic parameters of stutterers' habitual speech patterns and the patterns they display while speaking in the presence of such novel stimuli as DAF or masking. Second, investigators have undertaken the fiberoptic examination of stutterers' larynges during fluent and stuttered utterances. Third, there have been studies of the speed with which stutterers start and terminate voicing independent of the act of speaking. Finally, there have been investigations of possible perceptible differences between the fluency of stutterers and normal speakers. Each of these four types of research is examined. Tentative conclusions are drawn, and directions for future theorizing and experimentation are suggested.     

Vowel duration in stutterers participating in precision fluency shaping

The purpose of this study was to determine the extent to which stutters manipulate vowel duration to achieve fluency after participating in Precision Fluency Shaping. Nine stutterers who read an all-voiced sentence fluently before and after therapy were selected for study. Wide-band spectrograms were made of the initial phrase of the sentences, and vowel durations were computed. Results indicated that extended vowel durations were characteristic of the fluency of stutterers posttherapy. The subject that had the highest rate of disfluency after therapy also had the shortest vowel durations. Clinical implications concerning the importance of speech rate during carryover practice are made.     

Auditory processing and anxiety in stutterers

This study utilized the Synthetic Sentence Identification/Ipsilateral and Contralateral Competing Message subtests and the State-Trait Anxiety Inventory to examine auditory processing deficits, anxiety levels, and the interaction of these two components in 15 adult stutterers and 15 nonstutterers. Results support brainstem auditory processing deficits in stutterers and equalization of cortical functioning between groups. Group differences were not found in anxiety levels. Nonsignificant correlations between anxiety levels and auditory processing were revealed.     

Rate changes in the speech of stutterers after therapy

The fluent speaking rate of nine adult male stutterers was compared before and after stuttering intervention. The subjects, ranging in age from 18 to 37 yr (mean, 25 yr, 3 mo), exhibited mild to severe stuttering prior to treatment. The only rate reduction strategy taught to subjects during intervention was to slow the first phoneme or syllable of sentences spoken. In addition, however, subjects significantly reduced their overall rate as determined by measurements made of their fluent speech at the middle of sentences, as well as overall sentence durations (excepting the first word of utterances). The data from this investigation are interpreted relative to the facilitation/simplification hypothesis.     

Studies on the categorization of speech by infants

It is well-known that complexities exist in the mapping between the acoustic information in the speech signal and the phonetic categories of adult language users. We investigated whether the same complexities exist in the mapping between the speech signal and the forerunners of these categories in infants. For two classes of complexity, we found that the manner in which the categorization of information for speech occurs was virtually identical in infant and adult listeners. These findings indicate that the infant possesses finely tuned linguistically-relevant perceptual abilities, which undoubtedly facilitate and shape the task of language acquisition.     

Language and speech recovery in a case of viral encephalitis

The speech and language recovery course of a 47-year-old man with viral encephalitis is described. Over a 3-month period, the patient was evaluated six times using the same selected battery of tests. Results show that viral encephalitis can deleteriously affect communicative performance and that improvement in medical status is accompanied by rapid and dramatic gains on most standard speech and language measures. For this case changes appeared related to improved auditory attention and retention, increased efficiency in word retrieval, and improved mental status.     

Patterns of EEG alpha during word processing and relations to recall

EEG alpha activity was monitored during word presentation in a single trial cued-recall task. Initial post-word changes in alpha were related to a dimension of word meaning (arousal-neutral) while subsequent alpha asymmetry was a function of encoding instructions (verbal or visual). Initial bilateral reductions in alpha were associated with increased recall, but subsequent asymmetry in alpha was not. The results suggest a two stage pattern of cortical activation associated with memory storage processes.     

Vocal changes in stutterers and nonstutterers during monotoned speech

For years, reports have circulated that stutterers experience marked decrements in their stuttering when they speak or read in monotone. Wingate has suggested that the ameliorative effects of various novel speaking conditions on stuttering can be attributed to modifications in vocalization induced by such conditions. The present study was conducted to see whether this explanation would extend to monotoned speech as well. Ten teenage and adult stutterers and 10 normal speakers were tested in control and monotone reading conditions. Dependent measures were the frequencies of disfluency and stuttering, fundamental frequency, fundamental frequency standard deviation, vocal SPL, vocal SPL standard deviation, and fluent reading rate. Only within-group statistical comparisons were made, because members of the two groups could not be matched pairwise along critical vocal parameters. The major findings of this study indicated that across the two conditions, both groups significantly reduced their fundamental frequency, fundamental frequency standard deviation, vocal SPL and vocal SPL standard deviation. Only the stutterers exhibited a significant decrement in disfluency and stuttering. The normals did not evince enough disfluency in the control condition for a reduction to occur during monotoning. Neither group effected a reduction in fluent reading rates. These and other findings and interpretations are discussed relative to Wingate's modified vocalization hypothesis.     

The relevance of DAF-induced speech disruption to the understanding of stuttering

The literature on delayed auditory feedback (DAF) repeatedly makes reference to the occurence of disfluencies under DAF in nonstutterers. However, no attempt has been made to determine the relative frequency of occurence of various types of disfluencies in nonstutterers under DAF. The present study investigated the frequency of occurence of various types of disfluencies in normal-speaking subjects in five successive oral readings under DAF. Twenty-four young adults read aloud a prose passage five times successively under 200 msec of bilateral DAF. Measures of the frequency of different types of disfluencies, locus of occurence of disfluencies in the speech sample, adaptation and consistency indicate that DAF-induced disfluencies are remarkably similar to those found in stuttering. It is suggested that DAF and stuttering disrupt speech at approximately the same “level” along the speech production process, possibly at the prosodic level.     

Critical words and the locus of stuttering in speech

The locus of stuttering in the communicative speech of 26 stutterers was studied in situations where subjects received and conveyed specific information. It was hypothesized that a larger proportion of critical rather than noncritical words would be stuttered. Critical words were those which necessarily had to be pronounced if a listener should be able to understand and act according to the messages given. The critical words were selected by the experimenter before the experiment started. The results showed that 35.8% of the critical and 8.4% of the noncritical words were stuttered. There was also significantly more stuttering on critical words than on long noncritical words. The largest proportion of critical words appeared in the final position of sentences, which was also where most stuttering was located. Whole-word repetitions, an instance of normal nonfluency, were associated with noncritical words. No correlation between frequency of stuttering and whole-word repetitions was found.     

On the basis of early transitivity judgments

This research had two aims. The first was to test three explanations of performance on N-term series tasks by young children: the labeling model of B.DeBoysson-Bardies and K. O'Regan (1973), Nature (London), 246, 531–534, the sequential-contiguity model of L. Breslow (1981, Psychological Bulletin, 89, 325–351), and the ordered array or image model of C. A. Riley and T. Trabasso (1974, Journal of Experimental Child Psychology, 17, 187–202). In the first experiment, 5-year-old children were taught additional premises which would interfere with labeling and sequential-contiguity processes, but not with forming an ordered array. Reasoning performance was essentially comparable to previous results with the paradigm, thus supporting the ordered array model. The second aim was to reexamine children's ability to learn sets of premises which can be assembled into an ordered array, since there was reason to believe that previous studies had created false positives. In the second experiment, 3- to 7-year-old children were taught either overlapping (a > b, b > c, …) or nonoverlapping (a > b, c > d, …) premises. Overlapping premises can be integrated into an ordered array (a, b, c, d, e), but nonoverlapping premises cannot. However, the overlapping condition proved more difficult, and the success rate for preschoolers ($\text{3}\text{1}\text{2}\text{-}\text{to 4}\text{1}\text{2}\text{-year-olds}$) was of zero order. This raises doubts about their ability to learn a set of premises of the kind required for transitive inference. These doubts were strengthened by the third experiment which showed that when premises were not presented in serial order, preschool ($\text{3}\text{1}\text{2}\text{-}\text{to 4}\text{1}\text{2}\text{-year-old}$) children could not learn the premises of an N-term series task.