Michael L. O'Dell
Department of Finnish Language and General Linguistics,
University of Tampere
P.O. BOX 607,
33101 TAMPERE
FINLAND
Qualitative Factors in the Perception of Quantity (Abstract)
In Papers from the 18th Meeting of Finnish Phoneticians
(M. O'Dell, ed.), pp. 261-272. (1995) Tampere: University of Tampere.
Two perception experiments were conducted to explore the residual effects
of factors other than pure timing differences on the discrimination of the
Finnish words tuli ('fire') and tuuli ('wind'). Stimuli
were constructed from natural speech tokens of these words using LPC analysis
and LPC synthesis with stretching of the time parameter to form continua
from tuli to tuuli. In the first experiment, two stimulus
series were compared: one synthesized using the LPC parameters from original
tuli, the other using parameters from original tuuli. By appropriate
manipulation of the time parameter (as calculated by Dynamic Time Warping),
perception was indeed changed from tuli to tuuli in
both series (Figure 2). However, there was also a very significant effect
of residual factors (including spectral properties and fundamental frequency)
on responses. In the second experiment, spectral differences in the two
series were averaged out, leaving only a difference in fundamental frequency
(pitch period). The results were similar (Figure 8), although the effect
of the fundamental frequency difference alone was not as large as the total
residual effect in the first experiment. In addition, although significant
for the subject group as a whole, not all individual subjects exhibited
an effect for fundamental frequency alone.
Figure 2. % 'tuli' responses in the first experiment
Figure 8. % 'tuli' responses in the second experiment