The effect of segmental and suprasegmental corrections on the intelligibility of deaf speech

Abstract

Three experiments were conducted to study the effect of segmental and suprasegmental corrections on the intelligibility and judged quality of deaf speech. By means of digital signal processing techniques, including LPC analysis, transformations of separate speech sounds, temporal structure, and intonation were carried out on 30 Dutch sentences spoken by ten deaf children. The transformed sentences were tested for intelligibility and acceptability by presenting them to inexperienced listeners. In experiment 1, LPC based reflection coefficients describing segmental characteristics of deaf speakers were replaced by those of hearing speakers. A complete segmental correction caused a dramatic increase in intelligibility from 24% to 72%, which, for a major part, was due to correction of vowels. Experiment 2 revealed that correction of temporal structure and intonation caused only a small improvement from 24% to about 34%. Combination of segmental and suprasegmental corrections yielded almost perfectly understandable sentences, due to a more than additive effect of the two corrections. Quality judgments, collected in experiment 3, were in close agreement with the intelligibility measures. The results show that, in order for these speakers to become more intelligible, improving their articulation is more important than improving their production of temporal structure and intonation.

Fundamental Frequency as a Perceptual Cue for Vowel Identification in Speakers with Parkinson’s Disease

“…Findings from the present study suggest that it is the combined effects of segmental and suprasegmental impairments that lead to errors in vowel identifi cation as listeners are forced to adjust the weight of cues in the acoustic signal to optimize their perceptual strategies. Similar fi ndings have been observed in the speech of people who are deaf [21][22][23]45] . For highly intelligible speakers in the CG, on the other hand, acoustic characteristics of each vowel category were distinct and F0 was likely a redundant cue, therefore, manipulation of F0 did not affect the accuracy of vowel identifi cation.…”

“…Computer-implemented improvements in F0 contours for speakers with hearing impairments have been correlated with signifi cant improvements in speech intelligibility scores [21][22][23] . Osberger and Levitt [23] report that the extent to which intelligibility was altered as a result of suprasegmental modifi cations was directly related to the frequency of segmental errors, particularly vowel segments.…”

Word Deafness and Auditory Cortical Function: A Case History and Hypothesis

“…Subsequently formants were extracted with LPC-analysis and root-solving procedure using the ILS programming package (ILS, 1978). Next, the signal was resynthesized, applying a pitch synchronous energy correction (Maassen and Povel, 1985). Because plosives and vocal murmur deteriorate after resynthesis from formants, /ak/ was resynthesized from reflection coefficients, and the /b/ plus vocal murmur of the original spoken /bak/ was spliced in initial position in the resynthesized /bak/.…”

Relative Salience of Speech Rhythm and Speech Rate on Perceived Foreign Accent in a Second Language

“…Anderson-Hsieh, Johnson and Koehler (1992) used correlational methods and pronunciation ratings given to 60 non-native speakers, and also concluded that prosody makes a bigger contribution to accentedness than segments. Tajima, Port and Dalby (1997), Maassen and Povel (1985), Ulbrich and Mennen (2015) and Sereno, Lammers and Jongmann (2014), on the other hand, carried out a series of experiments and determined a much larger contribution of segmental features to foreign accent compared to suprasegmentals.…”