Yukio Takefuta

A Study of Pauses in Oral Reading of One's Native Language and English

Seventy-two students, representing equally Hindi, Spamsh, and Japanese speakers, served as experimental subjects. Each group was equally subdivided between students who were more and ones who were less proficient in aural comprehension of English. All participants recorded a philosophical essay in both their native language and in English. The statistical treatment was based upon the median duration of each speakers distribution of pauses in reading a two-minute portion of the passage. The groups of higher and lower levels of proficiency in the aural reception of English differed significantly both in the median length of pauses and the accompanying semi-interquartile range. Language groups differed in median duration of pauses, but not in semi-interquartile range. There was no difference in the length or distribution of pauses that the students used in reading in their native language and in English.

Intelligibility of speech signals spectrally compressed by a sampling-synthesizing technique

The purpose of this study was 1) to measure the intelligibility of speech signals processed with a frequency converter designed to effect a spectral compression by a sampling-synthesizing technique, and 2) to investigate the effect of a short training period on the perception of the speech signals so processed. The input signals were composed of 71 CVC words recorded by an American female speaker. The highest center frequency for the input of the 22 channels was 9500 Hz. The four compression ratios of the output to the fixed input frequency spectrum were 1.0, 0.7 0.5, and 0.4 for all 22 channels used. Eighty listeners were randomly selected and assigned to one of the four conditions of spectral compression. The intelligibility score of each condition of spectral compression was obtained from a multiple choice test of six possible choices for each stimulus. The average intelligibility score for all English phonemes was obtained for each condition of compression. The intelligibility of each vowel and consonant was also calculated for all conditions. Only 15 minutes of programmed training in listening to this processed speech was found to be significantly effective for improving perception in all four conditions.

Effect of normalization and transformation in the processing of F0 for analyzing American intonation

As any researchers who studied intonation know, this speech signal is an extremely difficult signal to analyze scientifically. Everytime they study it they find the necessity of studying more basic facts about it. Having learned this fact, this investigator collected samples of the simplest intonation, those of one word sentences, and examined the effect of normalization and transformation in the digital processing of physically extracted data F0 for the valid analysis and accurate detection of interrogative signals in American intonation. When optimal methods of normalization and transformation (ten methods tested) were applied, all interrogative intonations of ten different sentences (produced by 60 American speakers and validated by five native speakers of English) were perfectly distinguished from noninterrogative intonations. After these methods of normalization and transformation were applied to the physically extracted data, the basic interrogative intonation pattern and its variant for each of the...

Auditory recognition of intonation patterns

Intonation is considered to be represented by a pitch pattern. This pattern, however, is not obtainable in a traditional psychophysical experiment. It can be obtained only in an acoustico‐linguistic experiment, since physical parameters of speech signals are perceived in a special manner. Two methods can be considered for detecting the features used in the auditory recognition of intonation patterns: one is to collect all minimal contrasts in the language and find the smallest number of patterns necessary to distinguish all the contrasts; the other is to systematically transform the experimentally obtained patterns until a sufficiently large number of contrastive (not necessarily minimal) intonations are all distinguished. In such signals as intonation, which are extremely difficult to classify into minimal contrasts, the second method seems to be the only alternative. In this report, such a method of determining the auditorily perceived pattern of intonation is described. This study was conducted by simu...

Automatic Detection of English Stress

The object of this study was to examine the applicability of simple statistical methods in the processing of the acoustic parameters for automatic detection of English stress. Acoustic parameters such as the fundamental frequency, intensity, and duration were measured from 340 two‐syllable words recorded by 10 American speakers. These measures were then put into statistical transformations to simulate the human perception of the English stress. The relative efficiencies of these transformed parameters for the detection of stress signals were computed by calculating the classical indexes of signal detectability. No single parameter could perfectly predict the perception of the stress signals by human listeners. A further simulation of selecting, weighting, and combining the data of more than one of these transformed parameters, with a preset program, was made using a digital computer. The detection of stress signals by this computer simulation was found to be as accurate as detection by average native list...