Does Time Compression Decrease Intelligibility for Female Talkers More Than for Male Talkers?

Abstract

Purpose This preliminary investigation compared effects of time compression on intelligibility for male versus female talkers. We hypothesized that time compression would have a greater effect for female talkers. Method Sentence materials from four talkers (two males) were time compressed, and original-speed and time-compressed speech materials were presented in a background of 12-talker babble to young adult listeners with normal hearing. Each talker/processing condition was heard by eight listeners (total N = 64). Generalized linear mixed-effects models were used to determine the effects of and interaction between processing condition and talker sex on keyword intelligibility. Additional post hoc analyses examined whether processing condition effects were related to talker vowel space and word frequency. Results For original-speed sentences, female and male talkers were essentially equally intelligible. Time compression reduced intelligibility for all talkers, but the effect was significantly greater for the female talkers. Supplementary analyses revealed that the effect of time compression depended on both talker vowel space and word frequency: The detrimental effect decreased significantly as word frequency and vowel space increased. Word frequency effects were also greater overall for talkers with larger vowel spaces. Conclusions While the small talker sample limits conclusions about the effects of talker sex, the secondary analyses suggest that intelligibility of talkers with larger vowel spaces is less susceptible to the negative effect of time compression, especially for high-frequency words.

Figure 1.

Average percent correct sentence keyword identification scores for individual talkers in two conditions. The talkers are arranged from left to right in order of increasing vowel space perimeter. Error bars indicate 95% confidence intervals.

Figure 2.

Average time compression intelligibility decrements (in percentage points) as a function of talker vowel space perimeter (on the Bark scale). Error bars indicate Welch's t intervals for 95% confidence. The talkers with larger vowel spaces have smaller intelligibility decrements when their speech is time compressed.

Figure 3.

Average percent correct keyword identification scores for individual talkers as a function of word frequency (on the Zipf scale). The filled circles and solid regression lines represent keywords in the unprocessed condition. The open circles and dashed regression lines represent keywords in the time-compressed processing condition. The talkers are arranged from left to right in order of increasing vowel space perimeter. As vowel space perimeter increases, the slopes of the regression lines increase, especially in the time-compressed processing condition.