Processing Foreign-accented and Native-accented speech : An Electrophysiological Study on the Role of Exposure and Age
- Abdollahi, Fatemeh A
- [University Park, Pennsylvania] : Pennsylvania State University, 2019.
- Physical Description:
- 1 electronic document
- Additional Creators:
- Hell, Adriana Geertruida van, 1965-
- Graduate Program:
- Restrictions on Access:
- Restricted (Penn State Only).
- This dissertation examines the mechanisms underlying native- and foreign-accented sentence processing, in younger and older adults. Anecdotally, it is often reported that it is more difficult to understand foreign-accented speech, but what mechanisms actually underlie this difficulty, and how do listeners adapt to this variation? Behavioral studies have often reported rapid adaptation to variation in foreign-accented speech (e.g., Clarke & Garrett, 2004), but neurocognitive studies have found that processing of semantic and syntactic information in sentences produced by foreign-accented speakers can differ from that in sentences produced by native-accented speakers (e.g., Grey & Van Hell, 2017). To the best of my knowledge, to-date, no studies have examined the underlying mechanisms of foreign-accented speech processing in older adults, or the underlying mechanisms of foreign-accent processing, after systematic lab-based exposure, in younger adults. Across two experiments, I used EEG/ERP methodology to examine 1) whether structured exposure to foreign-accented speech affects grammatical and semantic processing in foreign-accented versus native-accented sentences in monolingual listeners with little prior exposure to foreign-accented speech (Experiment 1), and 2) whether processing of sentences produced in foreign- versus native-accented speech is different in older adults than in younger adults (Experiment 2). Neural activity associated with the processing of foreign- and native-accented speech was also related to listeners attitudes towards accented speakers, variation in linguistic and cognitive skills, and hearing acuity. In Experiment 1, I investigated whether systematic exposure to multiple foreign-accented speakers would transfer in online processing of a novel foreign-accented speaker. I found that intensive lab-based training facilitated speaker-independent adaptation, seen through significant sensitivity to both semantic and syntactic errors made by the novel foreign-accented speaker. Individual differences in linguistic, cognitive, or affective measures did not correlate with online sentence processing patterns. In Experiment 2, I found that, while older adults showed comparable neural sensitivity to semantic and syntactic errors in native-accented speech, there was no sensitivity shown online to semantic or syntactic errors produced in the foreign-accent, though offline older adults showed high comprehension accuracy to both native- and foreign-accented sentences. Hearing acuity and individual differences in cognitive and linguistic variables did not correlate with online processing patterns of foreign-accented sentences. Together, these experiments suggest that exposure to foreign-accented speech is key to adaptation, and that adaptation to foreign-accented speech does not occur in a matter of minutes, as previously proposed (Clarke & Garrett, 2004; Witteman et al., 2003), and varies as a function of aging. Through intensive and systematic exposure to foreign-accented speech, younger adults can show changes in underlying processing of complex syntactic errors in foreign-accented speech, suggesting that with increased reliability of input, listeners are able to extract speaker-independent phonetic cues, facilitating lexical access for higher-level semantic and syntactic processes. In contrast, while older adults show no age-related declines in processing of native-accented speech, the natural variability present across speech from a single foreign-accented speaker is not enough to elicit sensitivity online in foreign-accented speech. These findings provide clues of how we can more successfully scaffold communication between native and non-native accented speakers, in younger and older monolingual listeners.
- Other Subject(s):
- Dissertation Note:
- Ph.D. Pennsylvania State University 2019.
- Technical Details:
- The full text of the dissertation is available as an Adobe Acrobat .pdf file ; Adobe Acrobat Reader required to view the file.
View MARC record | catkey: 27983977