The Intelligibility of Natural and Vocoded Semantically Anomalous Sentences: A Comparative Analysis of English Monolinguals and German-English Bilinguals.

Abstract : This study analyzed the performance of 24 German-dominant German-English bilinguals and 24 English monolinguals on tests of semantically anomalous natural and computer-generated (vocoded) sentences. The primary objectives were: to determine whether the overall performance of the bilinguals was significantly worse than the monolinguals in response to natural and/or vocoded speech; to categorize the specific types of errors made by the two groups of subjects; and to analyze the patterns of errors made by the two groups in an attempt to evaluate their sentence-processing strategies. Results revealed that, overall, the bilinguals made more errors than the monolinguals did in response to both natural and vocoded speech. Both groups had a preponderance of phonemic rather than morpho-syntactic or lexico-semantic errors, and most errors were phonemic substitutions, rather than omissions or insertions. Results suggested that the bilinguals and monolinguals were using similar processing strategies. However, the bilinguals' pattern of errors indicated that they found both the natural and vocoded sentences tasks considerably more difficult than the monolinguals did, and the number of overall errors in the vocoded sentence task indicated a potential problem for communication systems of this type. It was also found that subjective task-difficulty ratings and English-proficiency ratings were correlated with test scores.