Vowels and speech production: gender differences

1. Vowels and speech production: gender differences Presentation from Lina Hecker Speaker Characteristics Venice International University Prof. Dr. Jonathan Harrington 17. October 2007

2. Introduction: • there have been some analyses of female speech in the past → focal point has been the male voice • female voice has a higher frequency range • men are more studied and they are regarded as the standard to which everything else is compared • in this lecture you can hear some differences in the speech of females and males based on adults • focus on dynamic articulatory and acoustic consequences of differences in male and female vocal tract dimensions • and the relationship between formant change and tongue movement

3. 1. What are the dynamic articulatory and acoustic consequences of differences in male and female vocal tract dimensions?(Simpson 2001) • Simply illustrated in Goldstein (1980) using the mid-sagittal vocal tract dimensions • models vocal tract growth from infant to adult and its acoustic products • Goldstein draws together available anatomical dimension data from a number of qualitative and quantitative different sources

5. Conclusion of Figure 1: • In the figure female stricture sizes are calculated as 80% of the male values. • It shows superimposed tongue positions for female (solid) and male (dashed) [i] and [a]. • The distance from male [a] to [i] is ~11% greater than the analogous female distance. • If you assume the same nominal articulatory speed and neglect inertia and acceleration, then the male V–V movement will also take 11% longer.

6. 2. The relationship between the size of oral structures and its implications forarticulatory displacement and articulatory velocity.(Kuehn & Moll 1976) • They showed that the subjects with larger oral structures, had larger articulatory displacement and employed greater articulatory velocity to traverse larger articulatory spaces. → focused on the general consequences of differences in oral structure size → did not discuss the more wide-ranging implications of their findings for gender specific consequences in articulatory behavior and its acoustic products

7. Explanation of Figure 2: • In the next figure you can see a hypothetical male and female F1 paths for open–close vowel movement, assuming the same nominal tongue body movement speed of 200mm/s. → the male acoustic trajectory lasts longer than the female one → the linear acoustic rate of change of F1 for females is ~35% greater than the male value. ==> female tongue covers a shorter distance to achieve analogous targets, and corresponds to a greater acoustic distance.

9. Conclusion of Figure 2: • males and females aim for analogous phonetic vowel targets in CVC sequences • if they move their articulators at the same speed, and if they are operating within the same durational framework → females reach their target earlier • female degree of openness is greater than the male one • females exhibit less undershoot than males → undershoot increases from close to open vowel categories ==> despite dimensional differences, targets are attained at approximately the same time with a difference in articulatory speed

10. 3. The Relationship between formant change and tongue movement main articulatory-acoustic patterns found in diphthongs (Simpson 2001) • average male and female pellet and formant tracks are similar in form • female speakers cover a greater acoustic space both in linear (Hz) and nonlinear (Bark) terms • The articulatory distance covered by the two posterior lingual pellets during the vocalic stretch is greater for male speakers • the dorso-tectal stricture size defined by the two posterior lingual pellets is smaller for female speakers throughout the vocalic stretch • mean pellet speeds are greater for male than female speakers

11. 3.1. Data: UW-XRMBDB (Westbury, 1994) • data set for examining gender-specific differences in the relationship between articulation and its acoustic products • contains acoustic and articulatory records from 26 female and 22 male speakers (age 18-37), speaking Upper Midwest dialect of Am. English • linguistic (e.g. reading text) and non-linguistic (e.g. swallowing) tasks • articulatory data consists of 8 gold pellets • 4 lingual pellets are placed along the midline of the tongue

13. 3.2. Method use stretches of utterance to investigate the dynamic relationship between acoustic and articulatory activity which fulfill 3 criteria • large amounts of articulatory and acoustic movement; • continuous voicing throughout the stretch to facilitate reliable automatic formant tracking; • repetition by the same speaker of the same expression containing a suitable stretch. “The coat has a blend of both light and dark fibers.” ‘‘Theyall know what I said’’

14. A: Formant analysis • analysis of the vocalic stretch of “they all” made with the ESPS program formant • nominal default value of F1 was increased by 10% to 550Hz for female speakers • analysis times were extended by 25ms beyond the segment start and end times • formant tracks of the 239 tokens were visually checked for tracking errors • each set of formant tracks was resampled to provide 11 temporally equidistant formant records • 11 points provide a good definition of formant movement throughout the vocalic stretch

16. B: Pellet position • pellet position of the UW-XRMBDB are stated in a coordinate system • The normalization method redefines the position of the pellets on the tongue surface, with respect to their distance from the tip of the upper incisors. • normalization allows to compare values from speakers with different palate outline lengths • raw pellet positions were averaged separately for males and females • male and female average palate outlines were created using individual palate outlines, resampled at 0,5mm intervals

18. 3.3. Results 3.3.1. Duration: • a one-tailed t-test for the V-V stretches shows that the mean female duration is greater than the male one → no significant difference was found between the male and female durations of the utterances • in other studies there were also found longer female durations for diphthongs (Simpson 2001) and monophthongs (Hillenbrand, Getty, Clark & Wheeler 1995)

19. 3.3.2. Formant tracks • at the 11 equidistant measurement points means and standard deviations of F1-F3 were calculated for males (right) and females (left) tokens. (next fig) • formant values for the V-V stretch for “they all” can only cautiously compared with the results found in the literature • speakers in the UW-XRMBDB speak an Upper Midwest American English • vowels are from the initial part of the utterance, particularly “they” being utterance-initial, unstressed and preceding a stressed back open vowel → expect a more centralized vowel than you would find in isolation or utterance finally

21. In the next figure you can see a graphical comparison of the mean male and female formant tracks, converted to the Bark scale. • In linear (Hz) terms, female acoustic excursion within the vocalic stretch is greater for both F1 and F2 • In non-linear (Bark) terms, situation is different. The mean tracks for F2 and F3 run parallel with little change and a distance between them throughout the vocalic stretch. • difference in mean F1 is 0,74 Bark at the beginning and is 1,58 Bark (more than twice) by the end of the stretch → suggesting a closer male vowel or a more open female quality → more open the vowel quality, the larger the difference becomes between female and male F1

23. Explanation of figure 5: • during vocalic stretch tongue body makes a small upward moving before moving backwards and downwards • F1 is determined by the apico-dental stricture of “they” over the initial part of the stretch (t1-t4) • at the final part of the stretch (t5-t11) the tongue body is lowered, resulting in an increase in the size of the dorso-palatal stricture defined by T2–T4 • F2 rises (t2-t4) to reach a plateau at (t3-t4) for the closing phase of the diphthong • F2 falls continuously as dorso-palatal stricture size increases and the tongue moves back • rise in F3 can be related to the lowering and backing of the tongue body causing pharyngeal narrowing

24. 3.3.3. Pellet position and speeds • Fig. 6 shows the pellet position of the 4 lingual pellets • T1-T4 at each of the 11 measurement points for female and male speakers • transformed and normalized values are shown in (a) • in (b) raw values are plotted together with average palate outlines and pharynx line segments can be seen • arrows indicate the direction of movement over time • (b) shows the mean size, shape and location of the male and female pellet trajectories • in the transformed data (a), the palate has been ‘flattened’ → must be interpreted more carefully

26. Explanation of Figure 6: • both transformed and raw data bring out the larger male dorso-palatal strictures defined by T3 and T4 • laminal and apical strictures are not different for males and females • transformed data encode the distance between the palate and the pellets • higher location of the female trajectories shows the different stricture size (T3-T4) • T-test proves that for females the palate-pellet distance for T3-T4 is smaller • average lengths of the pellet trajectories during the vocalic stretch are shorter for females

27. posterior male lingual pellets T3-T4 travel a greater distance than the female pellets and they stay in contrast to the smaller acoustic space traversed by the male speakers • these gender differences stand in contrast to findings in (Hashi et al. 1998) where no gender influence on isolated vowel tokens was found • male dorsum travels a greater distance in a shorter time period (see 1.Duration) than the female one because the mean speed of the male posterior pellets (T3-T4) is higher

28. Explanation of Figure 7: • the next figure summarizes the average pellet speeds at each of the 11 measurement points • for the anterior pellets T1-T2 the male and female speed is not significantly different over the whole vocalic stretch • for T3-T4 the initial and final portions are similar as well • whereas the mean speeds of T3-T4 are at the highest point you can see significantly higher male speeds → compensation by both males and females is necessary to achieve the same targets, despite differences in articulatory space

30. Conclusion of Figure 7: • gender-specific stricture differences are restricted to posterior region of the oral cavity → degree of male palatal doming is higher and creates a greater articulatory space to cross • there are nonuniform differences in the relation of oral to pharyngeal cavity length and nonuniform differences in palate shape → this has nonuniform dynamic consequences for tongue movement

31. 4. Discussion • for the same V-V sequences male and female tongue movements and their acoustic and perceptual products are similar in shape and structure • difference between male and female F1 increased acoustically with the degree of vowel openness • male speakers had a shorter stretch duration → the speed of tongue dorsum displacement was higher • size of male and female articulatory spaces is different and stands in an inverse relationship to the size of their acoustic products • for the V-V sequences male and female pellet tracks have a similar form and differ only in size and position

32. male and female speakers a operating with similar speeds of tongue movements • assume that the slower (female) articulatory movements require more time and faster (male) ones less • larger vowel space for women → women speak more clearly and articulate more because it is the prestige form for female • women produce longer vowels than men • possibly speakers adopt different articulatory strategies to arrive at tokens of the same phonological categories → many of the hypothetical consequences are speculation

33. → no proof whether 2 speakers aim for similar targets when they produce tokens of the same phonological categories in a language → no classification that tokens of the same phonological categories are equivalent in articulatory, acoustic and perceptual terms • several experiments draw conclusions based on a few informants → tendencies might be individual rather than gender based • many reasons for difference between male and female speech → women tend to have a greater variation in their speech → female speech has been seen more difficult to analyse

34. 5. References • Simpson, A. P. (2002). Gender-specific articulatory-acoustic relations in vowel sequences. Journal of Phonetics, 30(3):417-435. • Simpson, A. P. (2001). Dynamic consequences of differences in male and female vocal tract dimensions. Journal of the Acoustical Society of America, 109(5):2153-2164. • Samuelsson, Y. (2006) Gender effects on phonetic variation and speaking styles: A literature study. GSLT Speech Technology Term Paper, autumn 2006.

35. Goldstein, U. (1980) An articulatory model for the vocal tracts of growing children. Ph. D. Thesis, MA: M.I.T. • Hashi, M., Westbury, J. R. & Honda, K. (1998) Vowel posture normalization, Journal of the Acoustical Society of America, 104, 2426–2437. • Johnson, K., Ladefoged, P. & Lindau, M. (1993) Individual differences in vowel production, Journal of the Acoustical Society of America, 94, 701–714. • Kuehn, D. P. & Moll, K. L. (1976) A cineradiographic study of VC and CV articulatory velocities, Journal of Phonetics, 4, 303–320.

36. Thank you for listening!