Effects of auditory masking by white noise on variability of fundamental frequency during highly similar productions of spontaneous speech

Six adults (3 men, 3 women) produced highly similar spontaneous speech utterances during quiet and 90-dB SPL white noise. Although subjects' fundamental frequency (fo) was significantly increased when speaking in noise, their fo variability (coefficients of variation) throughout the utterance was not affected by the auditory disruption. This indicated that their ability to vary fo for linguistic stressing was preserved under short-term disturbed auditory feedback. These findings further supported the hypothesis that fo is under open-loop regulation.     

Processing of a speech signal and thereby necessary attention: a contribution to dual performance

Speech intelligibility during the performance of a second task (sorting of small plates), and the frequency of sorting in dependence of the phases of speech processing (input-processing-output) are investigated. A fixed speech level (65 dB) is combined with 5 different noise levels (55, 60, 65, 70, 75 dB). The speech material and the sorting task vary in difficulty (words, sentences, small texts; simple and complicated sorting). By rating 3 questions the subjective quality of both tasks is inquired. Main results: speech intelligibility and frequency of sorting vary in dependence of noise level; frequency of sorting varies in dependence of the phases of speech processing and speech material; subjective ratings are corresponding with the performance of both tasks.     

Reading and spontaneous speaking fundamental frequency of young Arabic men for Arabic and English languages: a comparative study

Speaking fundamental frequency (SFF), the average fundamental frequency (lowest frequency of a complex periodic sound) measured over the speaking time of a vocal or speech task, is a basic acoustic measure in clinical evaluation and treatment of voice disorders. Currently, there are few data on acoustic characteristics of different sociolinguistic groups, and no published data on the fundamental frequency characteristics of Arabic speech. The purpose of this study was to obtain preliminary data on the SFF characteristics of a group of normal speaking, young Arabic men. 15 native Arabic men (M age = 23.5 yr., SD=2.5) as participants received identical experimental treatment. Four speech samples were collected from each one, Arabic reading, Arabic spontaneous speech, English reading, and English spontaneous speech. Speaking samples, analyzed using the Computerized Speech Lab, showed no significant difference for mean SFF between language and type of speech and none for mean SFF between languages. A significant difference in the mean SFF was found between the types of speech. The SFF used during reading was significantly higher than that for spontaneous speech. Also Arabic men had higher SFF values than those previously reported for young men in other linguistic groups. SFF then might differ among linguistic, dialectical, and social groups and such data may provide clinicians information useful in evaluation and management of voice.     

Disfluent speech associated with brain damage

The frequency and type of disfluencies in the spontaneous speech of 15 people with Broca's aphasia and right hemiplegia was studied. Two aged-matched control groups (15 nonaphasic stroke patients with left hemiplegia and 15 normals) were also studied. The frequency of disfluencies in the speech of aphasics was three times greater than that in the speech of either control group. However, most of the disfluencies uttered by aphasics were of the types commonly found in speech of normals.     

The differential effect of three auditory stimuli on the frequency of stuttering behaviors

In view of the frequent clinical use of external auditory stimuli in fluency building programs, the purpose of the present experiment was to compare the effects of rhythmic pacing, delayed auditory feedback, and high intensity masking noise on the frequency of stuttering by dysfluency type. Twelve normal hearing young adult stutterers completed an oral reading (approximately 250 syllables) and conversational speech task (3 min) while listening to the three auditory stimuli and during a control condition presented in random order. The results demonstrated that during oral reading all three auditory stimuli were associated with significant reductions in stuttering frequency. However, during conversational speech, only the metronome produced a significant reduction in total stuttering frequency. Individual dysfluency types were not differentially affected by the three auditory stimuli.     

Spectral restoration of speech: Intelligibility is increased by inserting noise in spectral gaps

In order to function effectively as a means of communication, speech must be intelligible under the noisy conditions encountered in everyday life. Two types of perceptual synthesis have been reported that can reduce or cancel the effects of masking by extraneous sounds: Phonemic restoration can enhance intelligibility when segments are replaced or masked by noise, and contralateral induction can prevent mislateralization by effectively restoring speech masked at one ear when it is heard in the other. The present study reports a third type of perceptual synthesis induced by noise: enhancement of intelligibility produced by adding noise to spectral gaps. In most of the experiments, the speech stimuli consisted of two widely separated narrow bands of speech (center frequencies of 370 and 6000 Hz, each band having high-pass and low-pass slopes of 115 dB/octave meeting at the center frequency). These very narrow bands effectively reduced the available information to frequency-limited patterns of amplitude fluctuation lacking information concerning formant structure and frequency transitions. When stochastic noise was introduced into the gap separating the two speech bands, intelligibility increased for “everyday” sentences, for sentences that varied in the transitional probability of keywords, and for monosyllabic word lists. Effects produced by systematically varying noise amplitude and noise bandwidth are reported, and the implications of some of the novel effects observed are discussed.     

Forensic voice discrimination by lay listeners: The effect of speech type and background noise on performance

In forensic settings, lay (nonexpert) listeners may be required to compare voice samples for identity. In two experiments we investigated the effect of background noise and variations in speaking style on performance. In each trial, participants heard two recordings, responded whether the voices belonged to the same person, and provided a confidence rating. In Experiment 1, the first recording featured read speech and the second featured read or spontaneous speech. Both recordings were presented in quiet, or with background noise. Accuracy was highest when recordings featured the same speaking style. In Experiment 2, background noise either occurred in the first or second recording. Accuracy was higher when it occurred in the second. The overall results reveal that both speaking style and background noise can disrupt accuracy. Although there is a relationship between confidence and accuracy in all conditions, it is variable. The forensic implications of these findings are discussed.     

Converting between word and syllable counts in children's conversational speech samples

Several authors have suggested that it is possible to convert between word and syllable counts for basic clinical measurements such as the frequency of speech disfluencies or speaking rate in conversational speech samples. Based primarily on results from adults' speech samples, proposed conversion factors have averaged approximately 1.5 syllables per word. Because children produce fewer multisyllabic words than adults, this conversion factor is probably not appropriate for children's speech samples. This study sought to develop a more accurate conversion factor for children's speech by comparing syllable and word counts in spontaneous speech samples produced by 50 children, age 3 to 5. Analyses revealed an average ratio of 1.15 syllables per word, which was consistent across different subjects, across subject groups (children who stutter and children who do not stutter) and also, somewhat surprisingly, across age groups (3-year olds, 4-year olds, and 5-year olds). Results suggest that this constant conversion factor of 1.15 can be used to convert between word and syllable with sufficient precision to allow clinicians to compare their data to published guidelines and benchmarks about childhood stuttering.     

The mean fundamental frequency in stutterers and nonstutterers during reading and spontaneous speech

Corresponding to the higher tension of muscles involved in speech production, a higher mean fundamental frequency should be expected in stutterers as compared to nonstutterers. It could be shown by the change scores of the mean fundamental frequency from reading to free conversation that stutterers tend to have a higher fundamental frequency during spontaneous speech.     

Hearing speech in noise: seeing a loud talker is better

Seeing the talker improves the intelligibility of speech degraded by noise (a visual speech benefit). Given that talkers exaggerate spoken articulation in noise, this set of two experiments examined whether the visual speech benefit was greater for speech produced in noise than in quiet. We first examined the extent to which spoken articulation was exaggerated in noise by measuring the motion of face markers as four people uttered 10 sentences either in quiet or in babble-speech noise (these renditions were also filmed). The tracking results showed that articulated motion in speech produced in noise was greater than that produced in quiet and was more highly correlated with speech acoustics. Speech intelligibility was tested in a second experiment using a speech-perception-in-noise task under auditory-visual and auditory-only conditions. The results showed that the visual speech benefit was greater for speech recorded in noise than for speech recorded in quiet. Furthermore, the amount of articulatory movement was related to performance on the perception task, indicating that the enhanced gestures made when speaking in noise function to make speech more intelligible.     

INCREASING AUTISTIC CHILDREN'S DAILY SPONTANEOUS SPEECH

We investigated the effectiveness of teaching parents of 3 autistic boys to use a time delay procedure to increase their children's appropriate spontaneous speech in several naturally occurring daily settings (e.g., saying “good morning” in the morning). Generalization across settings and within settings across persons and locations was assessed. Variation in the children's spontaneous speech was also assessed. In addition procedural errors in the parents' use of time delay were calculated. Results indicated that all children increased their daily spontaneous speech and generalized their speech to other locations and persons.     

老龄化对F0轮廓线索在汉语言语识别去掩蔽作用的影响

动态基频(F0)轮廓有助于嘈杂环境下的言语识别,可以作为将目标语音从背景声中分离的知觉线索。本研究通过评估老年人与年轻人在言语掩蔽下聆听具有自然动态F0轮廓与对F0轮廓操作调节后的汉语语句的言语识别能力,探讨老龄化对F0轮廓线索在汉语言语识别去掩蔽作用中的影响。结果显示,在言语掩蔽下自然动态的F0轮廓比压扁或拉伸的F0轮廓更能帮助年轻人抵抗信息掩蔽识别目标言语;而老年人在言语掩蔽下却难以从动态F0轮廓线索中受益。研究结果揭示了老年人利用F0轮廓线索促进掩蔽下言语感知能力的老化特点。     

The impact of broadband noise on serial memory: changes in band-pass frequency increase disruption

Irrelevant sound consisting of bursts of broadband noise, in which centre frequency changes with each burst, markedly impaired short-term memory for order. In contrast, a sequence of irrelevant sound in which the same band-pass noise burst was repeated did not produce significant disruption. Serial recall for both visual-verbal (Experiment 1) and visual-spatial items (Experiment 2) was sensitive to the increased disruption produced by changing irrelevant noise. The results provide evidence that sounds that are largely aperiodic can produce marked disruption of serial recall in a similar manner to periodic sounds (e.g., speech, musical streams, and tones), and thus show a changing-state effect.     

Is language acquired through imitation?

The role of imitation in language acquisition is examined, including data from the psycholinguistic, operant, and social learning areas. From the psycholinguistic data, four empirical statements have been extracted: (1) there is no evidence that spontaneous imitations of adult speech influence grammatical development, (2) imitation of speech does not appear to occur with frequency beyond age 3 years, (3) speech and hence imitation are not necessary for the comprehension of linguistic structures, and (4) most utterances of a child are novel and therefore could not have been exactly modeled. The first and second propositions are seen to be based on a too restrictive definition of imitation-immediate and exact copying. Selective imitation-a functional relationship involving similarity of a particular form or function of the model's responses-is proposed as an alternative, thus leaving the validity of statements (1) and (2) in question. Concerning assertion (4), certain data from the operant literature are presented as evidence of the compatibility of novel responding and modeling, imitation, and reinforcement. Finally, it is proposed that statement (3) suggests a mechanism by which selective imitation can be understood. A three-stage process is proposed in which comprehension of a grammatical form sets the stage for selective imitation of that structure, which leads in turn to spontaneous production. Thus imitation is a process by which new syntactic structures can be first introduced into the productive mode.     

The role of social and material reinforcers in increasing talking of a disadvantaged preschool child

Adult social reinforcement and access to materials in the preschool were made contingent on the verbalizations of a 4-yr-old Negro girl with an extremely low frequency of talking. Though the teachers' social attention was always given immediately for all spontaneous speech, if the child's spontaneous verbalizations were requests for materials, those materials were withheld until she had responded to the teachers' questions about those materials. When she was silent, the teachers withheld their attention and the materials. A high frequency of verbal behavior was quickly established. When both teacher attention and materials were provided only when the child was not verbalizing, the child's frequency of talking immediately decreased. When social attention and materials were again made contingent upon spontaneous speech and answering questions, the child's frequency of talking quickly increased to its previous high level. The content of the child's verbal behavior which increased was primarily a repetition of requests to the teachers with little change noted in the non-request verbalizations, or verbalizations to other children. A further experimental analysis demonstrated that social interaction per se was not the reinforcer which maintained the increased verbalization; rather, for this child, the material reinforcers which accompanied the social interaction appeared to be the effective components of teacher attention.     

Effect of speech task on intelligibility in dysarthria: a case study of Parkinson's disease

This study assessed intelligibility in a dysarthric patient with Parkinson's disease (PD) across five speech production tasks: spontaneous speech, repetition, reading, repeated singing, and spontaneous singing, using the same phrases for all but spontaneous singing. The results show that this speaker was significantly less intelligible when speaking spontaneously than in the other tasks. Acoustic analysis suggested that relative intensity and word duration were not independently linked to intelligibility, but dysfluencies (from perceptual analysis) and articulatory/resonance patterns (from acoustic records) were related to intelligibility in predictable ways. These data indicate that speech production task may be an important variable to consider during the evaluation of dysarthria. As speech production efficiency was found to vary with task in a patient with Parkinson's disease, these results can be related to recent models of basal ganglia function in motor performance.