Constraints Ranking among Bilingual Nigerian Adult Aphasics

The speech of aphasics is a kind of language in which constraints are ranked differently from what obtains in the speech of non-aphasics. Bilingual aphasics rank constraints in ways that reflect that they have more than one language in their language faculty. Therefore, this paper examined the manner in which constraints are ranked among Nigerian adult aphasics, using 40 purposively sampled Yoruba-English aphasics from the University College Hospital, Ibadan, Nigeria. A normative text was given these subjects to read, and their speeches were tape-recorded. The data were analyzed perceptually. The frequency and percentage of each form of deviation noticed in their speeches were calculated. Optimality Theory was then used to explicate the way constraints were ranked by these subjects before those forms of deviation emerged as the optimal candidates. Three forms of deviation were discovered at the segmental level of their phonology, namely deletion, substitution and epenthesis. Generally, the subjects ranked constraints in ways opposite those of non-aphasics. Markedness dominates faithfulness in all their rankings.