A Phonetically-Based Optimality Theoretic Account of Consonant ...

conclusion that" gestural reduction plays the decisive role in the perceptual loss of the target
in [casual-speech] place assimilation l8 . "
4.3 Methodological Assumptions
The basis of this experiment is the observation that air flowing via the glottis into
the oral cavity will result in pressure build-up in the cavity if the incoming air cannot be
(sufficiently) vented, as in the case of a supra-laryngeal stop closure. Section 4.3.1
discusses some expected oral pressure patterns, considering factors such as the presence or
absence of incoming flow, the presence or absence of supra-laryngeal stop closure(s), and
the consequences of oral cavity expansion and compression. Section 4.3.2 summarizes the
methods and interpretations developed in Silverman & Jun (1994), which the present
experiment adopts.
4.3. 1 Relevant Factors in the Interpretation of Oral Pressure Data
The figures below provide schematic diagrams of the oral cavity. In Figures land
2, Points A and B correspond to different places of constriction: the lips and the glottis,
respectively. PA denotes the pressure behind constriction point A, or the pressure inside
the cavity enclosed by constriction points A and B. In Figures 1 a and 1 b, the glottis is
open, and air flows via the glottis into the oral cavity. When the lips are open, as
schematizedinFigure la, no pressure will accumulate in the oral cavity, and the pressure
behind constriction point A (W approximates the atmospheric pressure (to the left of point
A), conventionally zero. If the lips are closed, as in Figure 1 b, the incoming air flow will
result in a pressure build-up behind constriction point A: I will represent the positive
increase in pressure as ±p..
18 Note that reduction is limited to the pre-consonantal position in Korean, but occurs both preconsonantally
and pre-vocalically in Taiwanese. This difference will be addressed in Section 5.
17