Speech compression is a method of electromyographically reducing the speech signal, resulting in a decrease in the time required for presentation of a message by increasing the number of words per minute. Research in the area of speech compression has to this time been focused on determining the listener response by means of comprehension testing. While comprehension testing uncovers the individual's ability to resolve, organize, and recall a message at accelerated rates, it gives no information about the listener's psychophysical response to compression. Does the individual find listening to compression to be tension-provoking or stressful? Or can a listener accommodate accelerated speech without stress? The purpose of this study was to determine the individual's acceptance of compressed speech. "Acceptability" was operationally defined as finding no significant differences between tension levels produced while listening to normal speech rate as compared to tensions produced while listening to compressed speech rates. Tension levels were determined by an electromyograph which measures the amount of tension within a muscle. The specific hypotheses researched were: Hypothesis 1. Sampled muscular tension levels will differ significantly with Order of Presentation. Hypothesis 2. Sampled muscular tension levels will differ significantly with Rate of Presentation. Hypothesis 3. Sampled muscular tension levels will differ significantly between Males and Females. Hypothesis 4. Sampled muscular tension levels will show significant interaction between Order of Presentation and Rate of Presentation. Hypothesis 5. Sampled muscular tension levels will show significant interaction between Order of Presentation and Sex of the Listener. Hypothesis 6. Sampled muscular tension levels will show significant interaction between Rate of Presentation and Sex of the Listener. Hypothesis 7. Sampled muscular tension levels will show significant interaction among Order of Presentation, Rate of Presentation, and Sex of the Listener. A 6 x 3 x 2 factorial de sign was constructed to examine muscular tension levels. The controlled factors were Order of Presentation, Rate of Presentation, and Sex of Listener. Rate of Presentation included three speech sample s: normal (189 words per minute), speech compressed 25% (252 words per minute), speech compressed 50% (378 words per minute). These rates were arranged into six presentational patterns, composed of the three rates varied by its position within the sequence. Each Order of Presentation was presented to a male and a female listener, resulting in twelve subjects. The dependent variable was muscular tension within the trapezius muscle produced by the listener as he heard the experimental presentation. The sample was selected from speech students enrolled in Fundamentals of Speech at Portland State University. Winter Term, 1970. Apparatus used to collect tension level readings were: bipolar surface electrodes, differential amplifier, oscilloscope, stereo tape recorder, and multi-functioned voltmeter. The muscle tension levels were analyzed statistically by the three -factor analysis of variance test for significance. The finding of no significant differences at the. 05 level of confidence for any of the experimental conditions warranted rejection of the research hypotheses. The conclusion drawn from this finding was that compression within the limits used in this study is an acceptable mode of presentation based on the criterion that tension levels produced by compression differ only by chance from tension produced while listening to normal speech. It seems feasible, therefore, to substitute compression for normal speech in conditions where usage would be desirable.

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Typically, instructional designers introduce audio in multimedia environments when a) it appears to be necessary -- for example, to provide feedback; or b) accessibility, availability, and/or hardware issues are insignificant -- in other words, It's there -- -- It sounds good -- It should work -- Why not use it? However, rarely is a decision to use audio based upon a thorough understanding of why, from a learning perspective, it is appropriate or optimal to do so. Clearly a lack of such an understanding can, and often does, lead to the inappropriate use of audio as a useful instructional medium. This study is designed: (1) to investigate the educational value of compressed speech in a multimedia environment, and (2) to evaluate how rate of speech may influence learning in a multimedia setting. It is also concerned with ascertaining whether: a) the recall of information at various levels of compressed speech decreases when audio delivery-rate (words-per-minute) increases; b) there is an interaction between task completion time and recall of information at various levels of compression; and c) relative to recall, there is an interaction between audio delivery-rate and increasing exposure to an audio stimulus. One hundred and ninety-two undergraduate students enrolled in business courses in two southeastern regional universities located in North Carolina and Virginia were randomly assigned to one of three groups. The three experimental test groups were normal speech, 125 words per minute, compressed speech: 175 words per minute and 200 words per minute. In all groups, participants were asked to listen to the solution of the puzzle, given in one of the three presentation rates of speech and they were given three different puzzles to solve. All data were collected at each assigned computer workstation. Data analysis revealed a difference between the three treatment groups (125 wpm, 175 wpm, 200 wpm) in recall scores due to the rate of compression, no interaction between completion times and the recall of information based on compression rate, and a difference in recall scores between the three treatment groups and the amount of exposure to the audio stimulus. / Ph. D.

An adaptive optimal silence detector is designed and implemented in four speech coding schemes: N-bit PCM (N = 5 to 12), N-bit A-law PCM (N = 4 to 8), N-bit ADPCM (N = 3 to 8) and ADM (Adaptive Delta Modulation) for bit-rates of 16Kps, 24Kps and 32Kps. The amount of compression is approximately 35% for voice recordings such as radio newscasts, highly active conversations and readings from prepared texts. Subjective evaluation shows that the silence-edited versions (silence played back as absolute silence) have acceptability scores of 1.07 lower than the unedited versions with respect to a specific coding scheme for a score range of 1 to 5. With noise-edited versions (silence replaced by random noise during playback) the score degradation is 0.5. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The problem with which this investigation is concerned is that of determining if recent studies showing no significant comprehension loss at compressed rates were valid for a learning situation.

Time-compressed speech discrimination of children grouped as high and low risk on a reading-readiness test was examined. Children were grouped according to performance on a measure of reading-readiness skills. All passed a hearing screening at fifteen decibels for octave frequencies 250-4000 Hz. The Word Intelligibility by Picture Identification (WIPI) comprised the time-compressed speech task, in a sound field at seventy decibels Sound Pressure Level and zero degrees azimuth. The protocol for administration of the time-compressed speech task was sixty per cent time compression, then zero per cent time compression. Significant effects appeared for time compression ratio and test group. Average difference was twelve per cent and approximately eight per cent at zero.

Contemporary definitions of human listening suggest that it is a multi-dimensional phenomenon. Short-term and interpretative listening may be viewed as important aspects of the listening process. However, research in time-compressed speech has focused on listening comprehension while not adequately treating other important types of listening. A broader view of the listening process would include all of the skills considered relevant to everyday human communication. This study examined the effect of time-compressed speech on comprehensive, interpretative and short-term listening. The Kentucky Comprehensive Listening Test was used to measure the three types of listening. Cut and splice tape editing was employed in the development of four master test tapes: a control tape presented at normal rate and tapes with test stimuli time-compressed by 30%, 45%, and 60%. Each of four randomly selected groups, 120 total subjects, was exposed to one of the four test tapes. The data from the test administrations was analyzed by analysis-of-variance and simple means tests. Results indicate that a statistically significant amount of the variance in comprehensive, interpretative and short-term listening scores may be explained by the manipulated variable, time-compression. However, the amount of variance-accounted-for is relatively low for both short-term and interpretative listening. Closer examination of the data indicates that short-term and interpretative listening test scores do not significantly decay until a high level of time-compression (60%) is reached. Conversely, in the case of comprehensive listening, a relatively linear relation exists between degree of time-compression and test scores. Significant drops in mean scores were found at more moderate levels of time-compression. The findings are discussed in light of differences between short-term and long-term memory. Comprehensive listening, which relies upon long-term memory, may suffer from a lack of adequate processing and encoding time which may be induced by time-compression. Short-term and Interpretative listening are processes which rely primarily on short-term memory and may not be adversely affected until a level of time-compression is reached which impairs intelligibility. Implications are noted for future research and for educational applications.

The problem of this study was to assess the desirability and practicality of utilizing compressed speech as an instructional technique within a junior college setting.

The purpose of the study was to determine the effects of various rates of compressed speech instruction upon the listening comprehension of community college students. The primary objective of the study was to determine the degree to which two types of community college students, developmental and non-developmental, could recall factual and interential information from an uninterrupted forty-two-minute presentation which had been compressed to: 0% (175 words per minute), 33% (275 words per minute), and 57% (400 words per minute). The ability of each type of student and treatment type to recall information over time was measured. The study was conducted at a large urban community college in the Winter and Spring of 1980. One hundred thirty-one developmental and non-developmental subjects participated in the study. These two classifications of students were randomized into one of three groups. The three experimental groups heard the treatment material presented at a designated compression rate, and took a treatment post-test. All experimental subjects took a delayed post-test two weeks following treatment. The scores of one hundred twenty participants were used in the Lindquist Type III analysis of variance with repeated measures which was conducted on the post-tests and delayed post-tests. The results of the data analysis revealed significant differences in type of treatment, type of student, and time of testing with the following results: (1) subjects hearing the presentation at 0% compression had the highest scores. There was no significant difference between the scores of the 0% and 33% treatment groups. (2) non-developmental subjects scored significantly higher than developmental subjects on the treatments and (3) scores on the post-test were significantly higher than the delayed post-test. / Ed. D.

Use of time-compressed speech stimuli has been found to be clinically effective in differential diagnosis of lesions of the temporal lobe. However, notably absent from the literature is information concerning performance of adults on time-compressed closed-set speech discrimination tasks. The goal of this study mas to compare performance of 12 males and 12 females between age 50 and age 70 on a time-compressed closed-set speech discrimination test against the performance of 12 males and 12 females between age 10 and age 28 on the same task. The Word Intelligibility by Picture Identification test (WPI) was presented in both non-compressed and time-compressed conditions to all subjects. Previous research suggests that a difference in performance between age groups and between males and females in the older age group should be expected. Average results indicated negligible differences between age or gender groups under any of the conditions tested. Additionally, the test yielded perfect or near perfect scores for all subjects in the non-compressed condition. Lack of differentiation of results suggests that the Word Intelligibility by Picture Identification CUIPI) may be insensitive to the discrimination disorders expected in older adults, that the subjects included in the study were atypical of older adults in general and therefore such discrimination disorders did not exist in the sample, or that the subjects in the study uiere able to apply some type of compensatory strategies which resulted in the unexpected performance.