Author: Stefan Frisch and Richard Wright
Abstract:
Phonological speech errors provide important psycholinguistic evidence for the
representations of phonological theory. In an electromyographic (EMG) study of
experimentally induced phonological speech errors, Mowrey and MacKay (1990) found
that speech errors frequently occur at a sub-featural, gestural level, with no
apparent effect on the percept of the word. Based on these gradient errors, they
argue against speech errors as evidence for the segmental unit. Mowrey and
MacKayıs study considered the activity of a single muscle, and thus was unable to
determine whether single gestures acted independently of gestural constellations,
which may be equivalent to traditional segmental units. This study is a
preliminary report from an ongoing acoustic analysis of speech errors. The data
are tape recordings of an error inducing experiment using nonsense tongue
twisters. Recordings of a single speaker producing four different tongue twisters
targeting /s/ and /z/, e.g. sit zap zoo sip, were digitized and analyzed. Some
errors involved multiple changes in acoustic properties, including simultaneous
changes in periodicity, amplitude of frication, and duration, while others
involved a subset of these properties. This evidence suggests that errors can
occur at both the single gesture level, affecting non-contrastive acoustic
properties, and at the level of the gestural complex or segment, creating a
perceptible, linguistically contrastive change.