Speech Rate Conditions Research Articles

Listening effort under different rates of speech

Listening effort, the cognitive resources allocated to understand spoken language, is a critical issue in communication under adverse listening environments. The present study investigated how listening effort would be affected by differing speech tempos. The experiment involved 23 native Korean adults with normal hearing, who were presented with linguistically complex Korean sentences at five different speeds (35%∼200% of original time). The cognitive load associated with listening under various speech rate conditions was quantified employing a dual-task paradigm, where the increased listening effort would impair the performance on an additional cognitive task. Participants listened to the sentences while performing an n-back task and then repeated back the sentence they heard. The results found a significant effect of speech rate on the n-back task, with lower accuracies in the faster speech conditions. The additional task also increased the overall cognitive load of sentence recognition, leading to various speech errors, such as the omission of key content words, unnecessary additions, and substitutions with similar words. This demonstrates that increased cognitive load during listening impairs speech processing at multiple levels (e.g., semantic processing, retention of words in working memory), emphasizing the need to adjust speech tempos for better understanding and comfort in listeners.

Variation in Speech Intelligibility Ratings as a Function of Speech Rate Modification in Parkinson's Disease.

Purpose The aim of this study was to quantify changes in speech intelligibility in two cohorts of people with Parkinson's disease (PD; those with and without deep brain stimulation [DBS]) across a broad range of self-selected speech rate alterations in (a) read sentences and (b) extemporaneous speech (monologues). Method Four speaker groups participated in this study: younger and older controls, people with PD undergoing standard pharmaceutical treatment, and people with PD and DBS. Naïve listeners rated the intelligibility of read sentences and extemporaneous monologues, spoken by participants at seven self-selected speech rates from very slow to very fast. Intelligibility was modeled as a function of group, speech rate condition, and speech task. Results Overall, compared to habitual speech rate, slower speech rate conditions were not associated with changes in speech intelligibility, whereas faster-than-habitual conditions were associated in declines in intelligibility. Results were mediated by group and task effects, such that talkers with PD and DBS were more likely to see intelligibility benefits at slower self-selected speech rates and less likely to see detriments at faster rates, and these differences were amplified in monologues compared to sentences. Conclusion Findings suggest differences in the ways in which slower and faster speech rate adjustments impact speech intelligibility in people with PD with and without DBS, with the latter demonstrating greater magnitudes of change.

Methodology Matters: The Impact of Research Design on Conversational Entrainment Outcomes.

Purpose Conversational entrainment describes the tendency for individuals to alter their communicative behaviors to more closely align with those of their conversation partner. This communication phenomenon has been widely studied, and thus, the methodologies used to examine it are diverse. Here, we summarize key differences in research design and present a test case to examine the effect of methodology on entrainment outcomes. Method Sixty neurotypical adults were randomly assigned to experimental groups formed by a 2 × 2 factorial combination of two independent variables: stimuli organization (blocked vs. random presentation) and stimuli modality (auditory-only vs. audiovisual stimuli). Individuals participated in a quasiconversational design in which the speech of a virtual interlocutor was manipulated to produce fast and slow speech rate conditions. Results There was a significant effect of stimuli organization on entrainment outcomes. Individuals in the blocked, but not the random, groups altered their speech rate to align with the speech rate of the virtual interlocutor. There were no effect of stimuli modality and no interaction between modality and organization on entrainment outcomes. Conclusion Findings highlight the importance of methodological decisions on entrainment outcomes. This underscores the need for more comprehensive research regarding entrainment methodology.

Going With the Flow: An Examination of Entrainment in Typically Developing Children.

Purpose Conversational entrainment is the tendency for individuals to modify their behavior to more closely converge with the behavior of their communication partner and is an important aspect of successful interaction. Evidence of entrainment in adults is robust, yet research regarding its development in children is sparse. Here, we investigate the emergence of entrainment skills in typically developing children. Method Data were collected from a total of 50 typically developing children between the ages of 5 and 14 years. Children participated in a quasiconversational paradigm with a virtual interlocutor. Speech rate of the interlocutor was digitally manipulated to produce fast and slow speech rate conditions. Results Data from the fast and slow conditions were compared using linear mixed models. Results indicated that children, regardless of age, did not alter their speech to match the rate of the virtual interlocutor. Conclusions Findings suggest that entrainment in children may not be as robust as entrainment in adults and therefore not adequately captured with the current experimental paradigm. Modifications to the current paradigm will help identify a methodology sufficiently sensitive to capture the speech alignment phenomenon in children and provide much needed information regarding the typical stages of entrainment development.

Gestural Properties of the Non-Target Velar Stop /k/ and Its Variance with Respect to Supralaryngeal Constrictions in C2

In this study, we examine overlap-induced gestural properties in C1. Specifically, we examine the spatio-temporal properties of the non-target velar stop /k/ in Korean, as a function of three segmental contexts in C2 (pre-/h/, pre-/p/, and pre-/t/), two-boundary conditions, and two speech-rate conditions. The results show that gestural overlap with different supralaryngeal constrictions in C2 is positively correlated with the constriction duration of /k/, and is negatively correlated with the constriction maxima. Different constrictions in C2 distinctly affect the spatio-temporal properties of C1. The pre-/t/ context leads to distinct patterns in the C1 velar stop, compared to the pre-/h/ and pre-/p/ contexts. The pre-/t/ velar stops observed in most combinatoric phonological contexts have shorter constriction durations, and have greater constriction maxima for /k(#)t/. Greater constriction maxima is also observed for the within-word condition as well as for fast speech rate. The contradictory spatio-temporal properties of /k/ seem to be determined by physiological constraints on a consecutive lingual-lingual sequence, and by a higher jaw position facilitated by a coronal.

Intelligibility and acceptability of time-compressed utterances: an experimental study with blind and sighted listeners

This paper reports an experimental study on the impact of time-compressed speech on acceptability and intelligibility of utterances in Brazilian Portuguese. For the experiments, short audio sentences containing warning messages were used as stimuli. These sentences were recorded in a natural speech rate and then digitally manipulated to faster rates in a scalar fashion (from 9 to 19 syllables per second). Intelligibility and acceptability tests were then conducted with blind and sighted subjects. The results indicate that time-compressed speech has a significant impact on both acceptability and intelligibility of utterances for both groups of participants and that while blind subjects tended to give slightly higher acceptability rates across all speech rate conditions, sighted subjects performed better in the intelligibility experiment, what contradicts a trend that is often reported in the literature

Sensory feedback dependence hypothesis in persons who stutter

The present study investigated the role of sensory feedback (auditory, proprioception, and tactile) at the intra- and inter-gestural levels of speech motor coordination in normal and fast speech rate conditions in two groups: (1) persons who stutter (PWS) and (2) those who do not (PNS). Feedback perturbations were carried out with the use of masking noise (auditory), tendon vibration (proprioception), and nonwords that differed in the amount of required tactile lip contact (/api/ + tactile and /awi/ − tactile). Comparisons were also made between jaw-free and jaw-immobilized (with a bite-block) task conditions. It was hypothesized that if PWS depend more strongly on sensory feedback control during speech production, they would show an increase in variability of movement coordination in the combined presence of fast speech rates and feedback perturbations, in particular, when jaw motions are blocked and adaptations in the other articulators are required to achieve the task goals. Significant feedback perturbation effects were found for both groups, but the only significant between-group effect was found at fast speech rates in the jaw-free condition, showing that control speakers were more perturbed at the intra-gestural level of coordination than PWS when simultaneous (auditory, proprioceptive, and tactile) perturbations were present. The findings do not provide support for either the feedback dependency or the sensory deficit hypotheses described in the literature to explain movement characteristics found in fluent speech production of PWS.

A duration‐dependent account of coarticulation for hyper‐ and hypoarticulation.

Hyperarticulated and hypoarticulated speech are accompanied by spectral expansion and spectral reduction of vowel nuclei, respectively. These shifts in F1/F2 vowel space directly affect degree of anticipatory coarticulation in consonant + vowel sequences apart from traditional vowel context effects. Examining the opposite conditions of emphatic stress [Lindblom et al., J. Acoust. Soc. Am. 121, 3802–3813 (2007)] and faster speaking rates (Agwuele et al., Phonetica, in press) it was shown that coarticulatory effects could be documented independently of the expected vowel expansion/reduction effects. A modified locus equation regression metric was used in both studies to isolate alterations in F2 transition onsets due to prosodic and speech rate conditions apart from vowel space shifts per se. The current study provides a unified empirical and theoretical account for the opposite coarticulatory effects by providing duration data as the common variable tying both studies together. Articulatory and acoustic simulations of deeper (emphasis) and shallower (increased tempo) closures are provided to explain the shifts of observed F2 onsets relative to predicted F2 onsets due simply to expanded/reduced vowel space.

Effects of Instructor Speech Rate on Student Affective Learning, Recall, and Perceptions of Nonverbal Immediacy, Credibility, and Clarity

Although research indicates that speech rate affects perceptions of speaker credibility as well as persuasiveness and information recall, research has failed to address how instructor speech rate affects student perceptions and learning. This study randomly assigned basic communication course students to one of three speech rate conditions (slow, moderate, fast), using a videotaped lesson by an instructor. Findings revealed significant differences for credibility, affective leaning, and nonverbal immediacy, but did not reveal significant differences for recall or clarity. Implications for instructional practice and suggestions for future research are discussed.

Linguistically mediated visual search: The critical role of speech rate

Recent studies have shown that the presentation of concurrent linguistic context can lead to highly efficient performance in a standard conjunction search task by the induction of an incremental search strategy (Spivey, Tyler, Eberhard, & Tanenhaus, 2001). However, these findings were obtained under anomalously slow speech rate conditions. Accordingly, in the present study, the effects of concurrent linguistic context on visual search performance were compared when speech was recorded at both a normal rate and a slow rate. The findings provided clear evidence that the visual search benefit afforded by concurrent linguistic context was contingent on speech rate, with normal speech producing a smaller benefit. Overall, these findings have important implications for understanding how linguistic and visual processes interact in real time and suggest a disparity in the temporal resolution of speech comprehension and visual search processes.

Strength of German accent under altered auditory feedback.

Borden's (1979, 1980) hypothesis that speakers with vulnerable speech systems rely more heavily on feedback monitoring than do speakers with less vulnerable systems was investigated. The second language (L2) of a speaker is vulnerable, in comparison with the native language, so alteration to feedback should have a detrimental effect on it, according to this hypothesis. Here, we specifically examined whether altered auditory feedback has an effect on accent strength when speakers speak L2. There were three stages in the experiment. First, 6 German speakers who were fluent in English (their L2) were recorded under six conditions--normal listening, amplified voice level, voice shifted in frequency, delayed auditory feedback, and slowed and accelerated speech rate conditions. Second, judges were trained to rate accent strength. Training was assessed by whether it was successful in separating German speakers speaking English from native English speakers, also speaking English. In the final stage, the judges ranked recordings of each speaker from the first stage as to increasing strength of German accent. The results show that accents were more pronounced under frequency-shifted and delayed auditory feedback conditions than under normal or amplified feedback conditions. Control tests were done to ensure that listeners were judging accent, rather than fluency changes caused by altered auditory feedback. The findings are discussed in terms of Borden's hypothesis and other accounts about why altered auditory feedback disrupts speech control.

Effect of normal and fast articulatory rates on stuttering frequency

The effect of speech rate on stuttering frequency was investigated with 20 stutterers. Subjects read two different 300-syllable passages at a normal and fast speech rate. Stuttering counts and articulatory rate were determined for each speech sample. Articulatory rates were derived from portions of the passages that were perceptually fluent. No statistically significant difference in stuttering frequency was found between the two speech rate conditions ( p = 0.16) while a significant difference was observed for articulatory rate ( p = 0.0007). These findings suggest that increased articulatory rate does not determine stuttering frequency with the same consistency as does decreased articulatory rate. It was concluded that a single explanation of the relationship between speech rate and stuttering frequency in terms of speech timing complexity is inadequate.

Upper lip, lower lip, and jaw peak velocity sequence during bilabial closures: No differences between stutterers and nonstutterers

In the present study, movement timing of upper lip (UL), lower lip (LL), and jaw (J) was investigated. Twelve nonstutterers and nineteen stutterers were asked to utter the testwords /papapas/ and /sapapple/ under different stress and speech rate conditions. Contrary to earlier reports suggesting an invariant UL–LL–J peak velocity sequence in normal speakers and a more variant pattern in stutterers, it was found that nonstutterers as well as stutterers failed to show an invariant peak velocity sequence for bilabial closure and that stutterers and nonstutterers exhibited almost the same distribution of peak velocity sequences. The present results reveal strong intra- and interindividual variability in peak velocity patterns, and lead to the conclusion that a deviation from the UL–LL–J peak velocity sequence is not an indicator of a disturbed speech motor control process.