Investigating the relationship between average speaker fundamental frequency and acoustic vowel space size

Abstract

The purpose of this study is to investigate the potential relationship between speaking fundamental frequency and acoustic vowel space size, thus testing a possible perceptual source of sex-specific differences in acoustic vowel space size based on the greater inter-harmonic spacing and a poorer definition of the spectral envelope of higher pitched voices. Average fundamental frequencies and acoustic vowel spaces of 56 female German speakers are analyzed. Several parameters are used to quantify the size and shape of the vowel space defined by /iː ε aː [symbol: see text] uː/ such as the area of the polygon spanned by the five vowels, the absolute difference in F1 or F2 between /iː/ and /uː/ or /aː/, and the Euclidian distance between /iː/ and /aː/. In addition, the potential impact of nasality on the vowel space size is examined. Results reveal no significant correlation between fundamental frequency and vowel space size suggesting other factors must be responsible for the larger female acoustic vowel space.

Individual Differences in Speech Production and Perception

“…Most studies on differences between male and female speech have concentrated on acoustic differences, fewer have investigated potential articulatory variability� A very salient and highly investigated aspect is the larger acoustic vowel space in females� It has been found for several languages, such as American English (Diehl et al�, 1996), British English (Whiteside, 2001), German (Weirich and Simpson, 2014a) and Swedish (Simpson and Ericsdotter, 2007)� The differences between vowel spaces are not uniform, with differences between different vowel categories increasing as F1 and F2 increase� Thus, male and female speakers differ most in front and low vowels (such as /i:/ and /a/) and less in high back vowels (such as /u:/) (Fant 1966)� Various hypotheses have been proposed to account for this variability� While some focus on purely behavioral reasons, such as the sociophonetic explanation of females aiming at speaking more clearly than males (Bladon et al�, 1983;Henton, 1995), others emphasize physiological (sex-related) differences� One of the latter is the non-uniform difference between males and females in the relationship of pharyngeal and oral cavity (Chiba and Kajiyama, 1941;Fant, 1966Fant, , 1975Nordström, 1977;Winkler et al�, 2006;)� A third strand of possible explanations is based on acoustic-perceptual compensation (Goldstein, 1980;Ryalls and Lieberman, 1982;Diehl et al�, 1996)� The reasoning is as follows: The higher the fundamental frequency, the sparser the harmonics� The greater inter-harmonic spacing in higher pitched voices causes a poorer definition of the spectral envelope (and in particular of the formants)� From that it is hypothesized that the larger acoustic distance between female vowel targets compensates for the poorer spectral definition more typically found in high-pitched female voices� However, in a recent study of 56 female speakers with varying fundamental frequency (from 154 Hz to 234 Hz), we did not find a correlation between f0 and acoustic vowel space size (Weirich and Simpson, 2013) suggesting other factors (organic and/or learned) must be responsible for the larger female acoustic vowel space� Another explanation involves the underlying articulatory dynamics in producing the vowel space� Despite females having, on average, larger acoustic vowel spaces than males, Simpson (2001Simpson ( , 2002 found smaller articulatory vowel spaces in females than in males� In addition, Simpson (1998) found sex-specific differences in the relationship between formant values...…”

Organic Sources of Inter-Speaker Variability in Articulation: Insights from Twin Studies and Male and Female Speech

“…Most studies on differences between male and female speech have concentrated on acoustic differences, fewer have investigated potential articulatory variability� A very salient and highly investigated aspect is the larger acoustic vowel space in females� It has been found for several languages, such as American English (Diehl et al�, 1996), British English (Whiteside, 2001), German (Weirich and Simpson, 2014a) and Swedish (Simpson and Ericsdotter, 2007)� The differences between vowel spaces are not uniform, with differences between different vowel categories increasing as F1 and F2 increase� Thus, male and female speakers differ most in front and low vowels (such as /i:/ and /a/) and less in high back vowels (such as /u:/) (Fant 1966)� Various hypotheses have been proposed to account for this variability� While some focus on purely behavioral reasons, such as the sociophonetic explanation of females aiming at speaking more clearly than males (Bladon et al�, 1983;Henton, 1995), others emphasize physiological (sex-related) differences� One of the latter is the non-uniform difference between males and females in the relationship of pharyngeal and oral cavity (Chiba and Kajiyama, 1941;Fant, 1966Fant, , 1975Nordström, 1977;Winkler et al�, 2006;Fuchs et al�, 2008)� A third strand of possible explanations is based on acoustic-perceptual compensation (Goldstein, 1980;Ryalls and Lieberman, 1982;Diehl et al�, 1996)� The reasoning is as follows: The higher the fundamental frequency, the sparser the harmonics� The greater inter-harmonic spacing in higher pitched voices causes a poorer definition of the spectral envelope (and in particular of the formants)� From that it is hypothesized that the larger acoustic distance between female vowel targets compensates for the poorer spectral definition more typically found in high-pitched female voices� However, in a recent study of 56 female speakers with varying fundamental frequency (from 154 Hz to 234 Hz), we did not find a correlation between f0 and acoustic vowel space size (Weirich and Simpson, 2013) suggesting other factors (organic and/or learned) must be responsible for the larger female acoustic vowel space� Another explanation involves the underlying articulatory dynamics in producing the vowel space� Despite females having, on average, larger acoustic vowel spaces than males, Simpson (2001Simpson ( , 2002 found smaller articulatory vowel spaces in females than in males� In addition, Simpson (1998) found sex-specific diffe...…”

Sex, acoustic space and vowel centralization in Bogota Spanish

“…Sin embargo, las vocales abiertas presentan diferencias acústicas significativas entre hombres y mujeres en diferentes lenguas del mundo (Podesva y Adisasmito-Smith, 1999;DiCanio et al, 2015). Los estudios sobre lenguas germánicas muestran que el habla masculina favorece la reducción espectral y temporal de las vocales, mientras que las mujeres producen formantes que ocupan un espacio acústico amplio y una posición periférica (Traunmüller, 1988;Byrd, 1994;Whiteside, 1996;Ericsdotter y Ericsson, 2001;Simpson y Ericsdotter, 2007;Weirich y Simpson, 2013;Weirich y Simpson, 2015).…”

“…El análisis de los datos acústicos mostró que los formantes y el área vocálica no tienen una correlación con los valores de la f 0 . Esto sugiere, según los autores, que estas diferencias fonéticas están determinadas por factores anatómicos y sociolingüísticos, pero no por factores de tipo perceptivo (Weirich y Simpson 2013, p. 2972. Goldstein (1980, pp.…”