The current dissertation represents one of the first systematic studies of the distribution of speech errors within supralexical prosodic units. Four experiments were conducted to gain insight into the specific role of these units in speech planning and production. The first experiment focused on errors in adult English. These were found to be systematically distributed within the highest-level supralexical prosodic unit, the Intonational Phrase (IP), providing evidence for its psychological reality. The specific distribution of errors--fewest in unit-initial position, with a gradual increase in errors across the unit--was interpreted to suggest that the IP functions as a planning domain: the unit is activated as a whole, and activation gradually decays with time leading to an increase in errors. The second experiment was motivated by the idea that a decrease in IP activation is best understood in the context of working memory processes. Children's speech was examined in preference to adult speech because it is less automatized and so likely more influenced by working memory. The findings were that children with better working memories produced shorter IPs and relatively more anticipatory errors than children with poorer working memories. The results provided further evidence for the role of IPs in planning. The third and fourth experiments extended the investigation to another language, Korean, and examined the role of a mid-level prosodic unit, the Accentual Phrase (AP), in planning and production. The results indicated the same pattern of error distribution in the Korean IP as in the English IP. In contrast, more errors occurred in AP-initial position than in the second half of the unit, and the elicited errors tended to preserve AP-internal structure. The results were interpreted to suggest that the AP provides a structural frame within which elements are slotted for production. Overall, the results are consistent with the idea that these units play a critical role in the planning and production process. The results also suggest that different units within the prosodic hierarchy function differently: the IP functions as a planning domain, and mid-level units (i.e., AP) provide the structure needed to accomplish serial ordering in speech. This dissertation includes previously published co-authored material.

Speech in a noisy background presents a challenge for the recognition of that speech both by human listeners and by computers tasked with understanding human speech (automatic speech recognition; ASR). Years of research have resulted in many solutions, though none so far have completely solved the problem. Current solutions generally require some form of estimation of the noise, in order to remove it from the signal. The limitation is that noise can be highly unpredictable and highly variable, both in form and loudness. The present report proposes a method of recording a speech signal in a noisy environment that largely prevents noise from reaching the recording microphone. This method utilizes the human skull as a noise-attenuation device by placing the microphone in the ear canal. For further noise dampening, a pair of noise-reduction earmuffs are used over the speakers' ears. A corpus of speech was recorded with a microphone in the ear canal, while also simultaneously recording speech at the mouth. Noise was emitted from a loudspeaker in the background. Following the data collection, the speech recorded at the ear was analyzed. A substantial noise-reduction benefit was found over mouth-recorded speech. However, this speech was missing much high-frequency information. With minor processing, mid-range frequencies were amplified, increasing the intelligibility of the speech. A human perception task was conducted using both the ear-recorded and mouth-recorded speech. Participants in this experiment were significantly more likely to understand ear-recorded speech over the noisy, mouth-recorded speech. Yet, participants found mouth-recorded speech with no noise the easiest to understand. These recordings were also used with an ASR system. Since the ear-recorded speech is missing much high-frequency information, it did not recognize the ear-recorded speech readily. However, when an acoustic model was trained low-pass filtered speech, performance improved. These experiments demonstrated that humans, and likely an ASR system, with additional training, would be able to more easily recognize ear-recorded speech than speech in noise. Further speech processing and training may be able to improve the signal's intelligibility for both human and automatic speech recognition.

abstract: Children with cleft palate with or without cleft lip (CP+/-L) often demonstrate disordered speech. Clinicians and researchers have a goal for children with CP+/-L to demonstrate typical speech when entering kindergarten; however, this benchmark is not routinely met. There is a large body of previous research examining speech articulation skills in this clinical population; however, there are continued questions regarding the severity of articulation deficits in children with CP+/-L, especially for the age range of children entering school. This dissertation aimed to provide additional information on speech accuracy and speech error usage in children with CP+/-L between the ages of four and seven years. Additionally, it explored individual and treatment characteristics that may influence articulation skills. Finally, it examined the relationship between speech accuracy during a sentence repetition task versus during a single-word naming task. Children with CP+/-L presented with speech accuracy that differed according to manner of production. Speech accuracy for fricative phonemes was influenced by severity of hypernasality, although age and status of secondary surgery did not influence speech accuracy for fricatives. For place of articulation, children with CP+/-L demonstrated strongest accuracy of production for bilabial and velar phonemes, while alveolar and palatal phonemes were produced with lower accuracy. Children with clefting that involved the lip and alveolus demonstrated reduced speech accuracy for alveolar phonemes compared to children with clefts involving the hard and soft palate only. Participants used a variety of speech error types, with developmental/phonological errors, anterior oral cleft speech characteristics, and compensatory errors occurring most frequently across the sample. Several factors impacted the type of speech errors used, including cleft type, severity of hypernasality, and age. The results from this dissertation project support previous research findings and provide additional information regarding the severity of speech articulation deficits according to manner and place of consonant production and according to different speech error categories. This study adds information on individual and treatment characteristics that influenced speech accuracy and speech error usage. / Dissertation/Thesis / Doctoral Dissertation Speech and Hearing Science 2020

Children with speech delay (SD) have underlying deficits in speech perception that may be related to reading skill. Children with SD and children with dyslexia have previously shown deficits for distinct perceptual characteristics, including segmental acoustic structure and global acoustic structure. In this study, 35 children (ages 7-9 years) with SD, SD + dyslexia, and/or typically developing were presented with a vocoded speech recognition task to investigate their perception of global acoustic speech structure. Findings revealed no differences in vocoded speech recognition between groups, regardless of SD or dyslexia status. These findings suggest that in children with SD, co-occurring dyslexia does not appear to influence speech perception of global acoustic structure. We discuss these findings in the context of previous research literature and also discuss limitations of the current study and future directions for follow-up investigations.

Children with speech delay (SD) have underlying deficits in speech perception that may be related to reading skill. Children with SD and children with dyslexia have previously shown deficits for distinct perceptual characteristics, including segmental acoustic structure and global acoustic structure. In this study, 35 children (ages 7-9 years) with SD, SD + dyslexia, and/or typically developing were presented with a vocoded speech recognition task to investigate their perception of global acoustic speech structure. Findings revealed no differences in vocoded speech recognition between groups, regardless of SD or dyslexia status. These findings suggest that in children with SD, co-occurring dyslexia does not appear to influence speech perception of global acoustic structure. We discuss these findings in the context of previous research literature and also discuss limitations of the current study and future directions for follow-up investigations.

The purpose of this study was to determine the effect(s) of tinnitus maskers and tinnitus instruments on speech discrimination utilizing a population of subjects who currently have tinnitus and are presently wearing these devices. The hypothesis which guided this investigation states that there is no difference between discrimination scores with and without tinnitus maskers. In an attempt to test this hypothesis, speech discrimination scores were obtained from 26 listeners both in quiet and in the presence of cafeteria noise, with and without use of their tinnitus maskers.

The general purpose of this investigation was to specify further the activity of the pulmonary tract in esophageal speech. Specifically, the study sought to determine whether pulmonary airflow (PAF) rate varied in continuous speech as a function of manner of production, voicing, syllabic position, and perceived level of stoma noise. PAF rate variation was defined as the frequency and magnitude of changes occurring in association with the variables of this study. Six esophageal speakers utilizing the inhalation method of air intake were classified as high or low stoma (pulmonary) noise speakers on the basis of ratings by three speech pathologists. The /p, b, s, z/ phonemes were placed in arresting and releasing syllabic positions of single syllable words which were combined with other words to comprise two word phrases. The resulting eight phrases were uttered three times in random order by each speaker, while PAF rate was monitored at the tracheastoma, and recorded simultaneously with the phrases on the graphic printout. The graphic printout of the PAF rate curves revealed that air flowed from the stoma continuously throughout the phrase for each phrase and each speaker, but showed no fluctuations in rate within phrases for any of the variables of the study. Additionally, it was noted that PAF rate was not associated with perceived level of stoma noise.

The purpose of this study was to investigate the effects of increased intensity on the bone conducted speech discrimination ability of normal listeners utilizing standard audiological equipment. The NU-6 word lists were utilized to test the bone conducted speech discrimination skills of ten normal hearing subjects, 21 to 30 years of age, on standard clinical equipment. Both the hearing levels (dB HL) and the sensation levels (dB SL) of the test administration were considered. In general, it was recommended that 100 dB Hl is the most appropriate dial setting for the administration of bone conducted speech discrimination tests even though comparable speech discrimination scores may be obtained with a 95 dB HL dial setting. This study indicates that the most appropriate sensation levels for the administration of bone conducted speech discrimination tests are 55 and 60 dB SL. Most normal listeners can be expected to achieve a 55 dB sensation level at the limits of the speech audiometer (100 dB HL). Additionally, it was found that when bone conducted speech discrimination tests are administered at levels of less than 55 dB SL, the results may be compromised by variances that occurred in this normal hearing sample. Therefore, the clinical audiologist should accept bone conducted speech discrimination results as valid only when the scores obtained at 40, 45 and 50 dB sensation levels are within the limits of clinical normality (90% or better). Recommendations for further research are discussed.

Student speech-language pathologists begin their academic preparation as observers. Observations of the clinical management session are for the purpose of providing student clinicians with insight into the management process by providing clinical models. To make observation experiences meaningful there must be some guiding framework which will demonstrate the significance of behaviors observed.

Hoarseness seems to be the primary type of voice disorder occurring in school-aged children. Voice experts have suggested measurement of maximum phonation times as a clinical tool for assessing vocal function (Fairbanks, 1940; Westlake and Rutherford, 1961; Irwin, 1965; Boone, 1971). Most of the studies on duration of phonation have used adults as subjects; few investigations have involved children. An apparent need, therefore, existed to investigate duration of phonation in young children.