Acoustic and laryngographic measures of the laryngeal reflexes of linguistic prominence and vocal effort in German

Abstract

This study uses acoustic and physiological measures to compare laryngeal reflexes of global changes in vocal effort to the effects of modulating such aspects of linguistic prominence as sentence accent, induced by focus variation, and word stress. Seven speakers were recorded by using a laryngograph. The laryngographic pulses were preprocessed to normalize time and amplitude. The laryngographic pulse shape was quantified using open and skewness quotients and also by applying a functional version of the principal component analysis. Acoustic measures included the acoustic open quotient and spectral balance in the vowel /e/ during the test syllable. The open quotient and the laryngographic pulse shape indicated a significantly shorter open phase for loud speech than for soft speech. Similar results were found for lexical stress, suggesting that lexical stress and loud speech are produced with a similar voice source mechanism. Stressed syllables were distinguished from unstressed syllables by their open phase and pulse shape, even in the absence of sentence accent. Evidence for laryngeal involvement in signaling focus, independent of fundamental frequency changes, was not as consistent across speakers. Acoustic results on various spectral balance measures were generally much less consistent compared to results from laryngographic data.

Vocal fold vibratory patterns in tense versus lax phonation contrasts

“…That there are so many significantly different landmark measures suggests that the overall pulse shapes differ. Therefore, following Mooshammer (2010), this study adopted…”

“…It can be seen that for each factor, either the positive or the negative factor value reaches the maximum normalized amplitude of 1.0, while the other factor value does not 11 . To help understand the meaning of the positive/negative deviations from average pulses seen in Figure 5, Figure 6 provides a graphical representation of the relevance of the experimental factors on each of the four principal components of the shapes, following Mooshammer (2010). For each sex by phonation by tone condition (there are 8 of these, e.g.…”

“…In order to cancel the effect of the length of the pulses due to f0 differences, the selected pulses were time-normalized to a uniform length of 1000 samples by a Matlab script using linear interpolation, just as in Mooshammer (2010). The pulse pairs were then amplitude normalized by setting both decontacting peaks in the EGG signal to 0, and then setting the amplitude of the highest EGG peak in each pair to 1.…”

“…All aspects of the Functional Data analysis of EGG pulses presented here follows the procedure by Mooshammer (2010). A subset of the tokens in the corpus was selected for this analysis: the consonant-vowel combination [be] was chosen, with all values of phonation type (lax vs. tense) and tone (low vs. mid).…”

“…Before analysis, the two pulses were pre-processed by a Fourier function, as recommended for periodic waves (for choices of different basis functions, see Ramsay and Silverman 2002). Following Mooshammer (2010), the number of Fourier coefficients was set to 200, and data smoothing is done with the third order of derivative whose square is integrated and weighted by lambda as 10E−12. After pre-processing, a FPCA was applied (Ramsay andSilverman, 1997, 2002) to identify the main factors of variability in the EGG pulses.…”