VOWELS IN STANDARD AUSTRIAN GERMAN - Acoustics ...

177
Vowels in Standard Austrian German
A subsequent study (Brunner et al. 2005) showed that subjects with a flat palate are
allowed less articulatory variability because slight displacements would result in great
changes in the acoustic output, whereas subjects with dome shaped palates are allowed
more articulatory variability, which they can employ or not.
These results strongly suggest that “the objective of speech articulation is to
produce an acoustic signal with properties that will enable the listener to understand
what is said” (Perkell 1997: 363). Within the Acoustic Invariance Theory, some of these
properties have to be invariant. Blumstein & Stevens (1979), who showed that the stop
place of articulation can be arranged according to spectral properties of the burst
(diffuse-raising, diffuse-falling and compact), conclude:
“In particular, it has been shown that the speaker provides the listener with invariant acoustic
cues, cues which can be directly derived from the speech signal itself. Thus, the interface
between the perceptual and production systems resides in the acoustic signal where the
properties of speech can be uniquely and invariantly specified.” (Blumstein & Stevens 1979:
1015)
Despite these initially promising results with respect to the stop place of articulation
(see also Blumstein & Stevens 1980, Stevens & Blumstein 1978, Lahiri et al. 1984,
Blumstein 1986), the search for an invariant acoustic property was unsuccessful.
Löfqvist (1986) argued for a separation of phonetics and phonology in order to get away
from a concept that sees invariance in terms of static entities. In a similar way, Fant
(1986) doubts “the absolute invariance of feature correlates irrespective of context”
(1986: 486) and suggests a context-dependent analysis instead:
“In my view, human speech perception relies on gestalt decoding rather than on isolated
short-time spectral patterns or templates. […] The auditory system probably makes efficient
use of the entire evidence available. Why should we limit our descriptive work to less
precise specifications or to a diluted specification which can operate in all contexts?” (Fant
1986: 487f)
Yet, results on the role of context in vowel perception are not unanimous. The theory of
the dynamic specification of vowels (Strange 1998, Strange & Bohn 1998, Jenkins et al.
1999) states that vowels in continuous speech are better identified when context is
available, whereas the results of Nearey & Assmann (1986) and Andruski & Nearey