Maria-Josep Solé*, Ronald Sprouse# and John Ohala#
* Universitat Autònoma de Barcelona, Spain
# Department of Linguistics, University of California, Berkeley


This talk explores how ways to facilitate voicing in obstruents have made
their way into the phonology resulting in different cross-linguistic
patterns. The relative difficulty of maintaining voicing during a stop has
been the object of extensive investigation (e.g., Ohala 1983; Westbury and
Keating 1986) and is at the origin of the 'aerodynamic voicing constraint'
(AVC) by which obstruents tend to devoice in a few tens of ms. in the
absence of additional articulatory maneuvers. Maintaining vocal fold
vibration during the obstruent constriction is crucial in languages which
use this cue (i.e., prevoicing) to signal the voicing contrast in
obstruents. A number of articulatory maneuvers may be used (singly or in
combination) to accommodate the air flowing through the glottis, and thus
prolong vocal fold vibration during the stop closure, for example, active
expansion of the oral cavity --by lowering the larynx or relaxing the
walls of the supraglottal cavity--, nasal leakage, oral leakage, or
diminishing the airflow into the oral cavity by increasing the tension of
the vocal folds (Rothenberg 1968; Ohala 1976; Ohala and Riordan 1979;
Westbury 1983; Svirsky et al. 1997). Languages (or dialects) may differ in
the articulatory adjustments used to avert obstruent devoicing and sustain
vocal fold vibration, and such differences give rise to cross-linguistic
phonological patterns. We will review a number of sound patterns
reflecting the phonologization of a variety of articulatory adjustments.
Specifically, we will explore (1) nasal leakage giving rise to emergent
nasals in an oral context and the preservation of the voicing contrast
exclusively postnasally; (2) larynx lowering and implosivization of stops;
(3) tongue-tip retraction and tongue body lowering, in the case of apical
stops, leading to retroflexion; (4) oral leakage (due to reduction in
magnitude and/or time of the closure gesture) and the spirantization of
stops. We will illustrate these processes with physiological data and
aerodynamic modeling. Experimental data on the effect of oral pressure
variations (e.g., due to oral cavity expansion) on voicing initiation and
continuation will be presented. Aerodynamic modeling allows us to simulate
articulatory adjustments and observe the associated aerodynamic effects on
voicing in order to test the validity of our claims. The aerodynamic
processes leading to the observed data (and phonological patterns) have
been modeled using Sprouse's (2008) aerodynamic model (a Matlab
implementation of Ohala's (1976) model). Even though the model does not
yet include vocal fold vibration, it can indicate when the critical level
for voicing is reached. Finally, it is argued that many cross-linguistic
patterns emerge from the different ways languages deal with physiological
and acoustic-auditory constraints.