1. Graduate School of Language Technology
Swedish National
Graduate School of Language Technology
Formant Synthesis of Speaker Age (+ a question regarding prosodic timing)
Susanne Schötz
Centre for Languages and Literature
Lund University

2. A Prototype System for Analysis of Speaker Age by Formant Synthesis

3. background (1): speaker age
acoustic cues to speaker age in almost every phonetic dimension
relative importance of these cues not fully explored
one reason: the lack of an adequate analysis tool (where a large number of potential age parameters can be varied systematically and studied in detail)

4. background (2): formant synthesis
robust & flexible, but not as natural-sounding as concatenation synthesis
GLOVE (OVE III with improved glottal source, dev. at Royal Institute of Technology, Stockholm) used in experiments of voice variation since 1989 (Carlson et al., 1991; Karlsson, 1992)
data-driven formant synthesis (GLOVE) (Sjölander, 2001; Sigvardson, 2002; Öhlin, 2004)
GLOVE = OVE III with enhanced glottal source; Glottal OVE
Assisting supervisor: Rolf at CTT, KTH

5. purpose & aim
develop a prototype system for analysis of speaker age by data-driven formant synthesis
use as a tool to analyse, model and synthesize speaker age

6. material 1 word: ‘själen’ [ˈɧɛːlən] (the soul)
4 speakers (same dialect & family)
speaker 1: a granddaughter (aged 6)
speaker 2: a daughter (aged 36)
speaker 3: a mother (aged 66)
speaker 4: a grandmother (aged 91)

7. material: acustic “pre-analysis”
som användes när jag byggde systemet
F0-contours for ['ɧɛːlən] + F1-F2 plot for the steady-state part of [ɛː]

8. method (1) data-driven analysis by synthesis (GLOVE, Praat, Perl)
automatic extraction of 23 GLOVE parameters (once every 10 ms)
formant synthesis (GLOVE)
audio-visual comparison of synthesis to original
parameter adjustment rules

9. results: speaker 1 (6 years)
original synthesis
+ fricative, creak
- formant error, amplitude

10. results: speaker 2 (36 years)
original synthesis
+ formants, F0
- dull

11. results: speaker 3 (66 years)
original synthesis
+ formants, F0
- amplitude, dull

12. results: speaker 4 (91 years)
original synthesis
+ formants, F0 (incl. creak)
- amplitude, fricative, dull

13. method (2)
weighted linear interpolation between two source speakers to synthesize a target age (Praat, Java)
ex. target age: 51
source speakers: 2 (36) and 3 (66)
age weights for each source speaker: 0.5
duration interpolation for segment 1: (source speaker 2 dur = 100 ms, source speaker 3 dur = 200 ms)
target dur = 100 x x 0.5 = 150 ms

14. results (interpolation)
at a first glance: similarities…
…linear interpolation not optimal: aging is not linear!
only first attempt
how evaluate?
- perception tests (31 students)
age
(naturalness)

15. evaluation results: natural speakersCA PA 6 7 36 30 66
35/36 91 74

16. evaluation results: data-driven synthesis
”CA” PA 6 12 36 41 66 44 91 69

17. evaluation results: linear age interpolation
”CA” PA 10 13 20 63 30 54 40 42 50 60 70 58 80

18. summary & discussion (1)
both similarities and differences between original and synthesis
a good start, but needs more work
formants
amplitudes
voice source parameters
try other interpolation algorithms (spline?)
if developed further, may be used to to model and synthesize speaker age

19. Question about prosodic timing
Bruce (1983): strong Swedish dialect -> later tonal peaks
older speakers often sound more dialectal (Stölten & Engstrand, 2003)
could prosodic timing be age-related?
my hypothesis: older speakers ->
later tonal peaks.
investigated 1 word ’Nordanvinden’ (4 speakers)

20. F0 contours for ’nordanvinden’6 66 36 91

21. F0 contours for ’nordanvinden’6 66 H H 36 91 H H

22. Questions What have I missed? How do I proceed?
synchronisation to segments?
context effects? …?
How do I proceed?
suggestions?
Do you (as prosodic experts) believe that there may be a relation between age and prosodic timing?

23. questions, answers and comments welcome!
thank you!
questions, answers and comments welcome!