206 Cynthia G. Clopper
Taken together, the results of these studies contribute to our understand-
ing of the nature of naïve listeners’ perception of both linguistic and social
information in the speech signal. Naïve listeners can explicitly identify both
linguistic and social categories from short speech samples. The perception of
linguistic categories is signi¿ cantly affected by both small acoustic changes
in the stimulus materials and variation due to surrounding acoustic context.
In addition to examining the effects of talker differences on perception,
the methods described previously can also be applied to investigations of the
role of the listener’s background in speech perception and spoken language
processing. By comparing the performance by multiple groups of listeners
with different backgrounds or experiences in the same task, we can explore
the relationship between linguistic experience and spoken language process-
ing. For example, Tees and Werker (1984) investigated the effects of linguistic
experience on the discrimination of Hindi retroÀ exed and dental stops. Native
English listeners with early exposure to Hindi and those with ¿ ve years of
experience with Hindi as adults performed the task well above chance. Native
English listeners with only one year of experience with Hindi and those
trained on the two phoneme categories in the laboratory exhibited chance
performance on the same task. Thus, familiarity with a given phoneme con-
trast affects the perception of those phonemes in an explicit discrimination
task. We would predict that a listener’s experience would similarly affect the
perception of both linguistic and social categories in the speech of talkers
from familiar and unfamiliar dialects.
A number of researchers have recently begun to apply speech science
methods to sociophonetic perception research. Carefully designed perception
experiments with naïve listeners have provided new insights into what naïve
listeners know about sociolinguistic variation, including how linguistic con-
trasts are perceived cross-dialectally and how social sources of information
in the speech signal are perceived. The role of the listener’s experience with
variation has also been examined by comparing performance in these types
of tasks across different listener populations. Sociophonetic studies of the
perception of linguistic categories have focused primarily on vowel identi-
¿ cation tasks, while the studies of social categories have typically examined
the perception of regional dialect variation in the United States.
- Perception of linguistic categories
Some of the most well-documented sources of regional dialect variation in the
United States are ongoing shifts in the vowel systems of northern and southern