|Title:||The Effect of Brain Damage and Linguistic Experience on Shona Lexical Tone Processing||Add Dissertation|
|Author:||McLoddy Kadyamusuma||Update Dissertation|
|Email:||click here to access email|
|Institution:||Universität Potsdam, International Master’s / Doctoral Program Experimental and Clinical Linguistics|
|Abstract:||This dissertation investigates the effect of brain lesions and linguistic
experience on the processing of Shona lexical tone. The first two studies
focus on hemispheric lateralization of lexical tone in Shona brain damaged
patients in order to establish the roles played by the left and right
cerebral hemispheres in the processing of lexical tone (Van Lancker, 1980).
Whereas Study three focuses on the influence of linguistic experience with
pitch contrasts on the ability to perceive Shona lexical tone in non-native
speakers (Thai and German) with an emphasis on the strategies used by the
Study 1 examined the ability of Shona speakers with unilateral left and
right hemisphere lesions to produce and identify lexical tone in disyllabic
words using a confrontational naming task and a picture identification
task. The study revealed that the left hemisphere (LH) damaged patients are
more impaired than right hemisphere (RH) damaged patients in their ability
to identify lexical tone indicative of a left hemisphere preferential role
in tone perception in Shona. On the other hand, there was no difference in
the ability to produce tone in left and right hemisphere damaged patients,
showing that tone perception and tone production can be differentially
disrupted after brain damage.
Study 2 further explored the effect of brain damage on the perceptual
discrimination of lexical tone in Shona speakers in a linguistic (pitch
used phonemically in Shona disyllabic words) and non-linguistic context
(low-pass filtered speech). The two tasks were meant to test the
differential processing of pitch either in the left or right hemisphere.
The results demonstrated that the performance of the LH damaged patients
was more reduced than that of RH damaged patients in both contexts, though
the performance of the RH damaged patients was not error free. From this we
concluded that the LH is more involved and dominant in the processing of
Shona lexical tone. Findings from the first two studies show that though
the LH is more involved in the processing of Shona lexical tone, the RH
also plays a part since no patient had near normal performance.
Study 3 examined the perceptual discrimination of Shona, Thai and German
speakers by exploring the effect of linguistic background on the ability to
perceive a typologically different tone language, Shona. The three groups
differed with regards to experience with manipulation of pitch. German
speakers had experience with pitch contrasts at the sentential level, while
Thai and Shona had experience with pitch at the syllabic level. The three
groups were examined using disyllabic words and low pass-filtered speech.
Experiment 1 tested the perceptual discrimination of Shona minimal pairs,
whereas experiment 2 tested both minimal and non-minimal pairs. The results
revealed that linguistic experience with a tone language aids the
perception of a typologically different language. However, the three groups
use different strategies based on their native phonological contrasts to
distinguish unfamiliar contrasts using selective processing.