MORPHOSYNTACTIC FEATURES OF SELECTED BILINGUAL APHASIC AND AUTISTIC SPEECHES IN SOUTHWESTERN NIGERIA

Abstract

Communication with, and speech rehabilitation of, Bilingual Aphasic Patients (BAPPs) and Bilingual Autistic Patients (BAUPs) have been characterised by difficulties arising from patients’ deficiencies in the formal features in English as a Second Language (ESL). Previous studies on the patients’ speech disorder have examined their phonological and pragmatic features, while the morphosyntax has remained underexplored in ESL situations. Morphosyntactic features of selected BAPPs’ and BAUPs’ speeches were therefore investigated in order to characterise the nature of speech impairments in BAPPs and BAUPs in Southwestern Nigeria. Halle and Marantz’ Distributed Morphology, which embodies the relationship between rules for deriving complex words and syntactic structures, and Chomsky’s Principles and Parameters Theory, which provides interacting principles for assessing competence in natural language processing were adopted as framework. Ethnographic techniques were adopted. Using Kirkwood’s sample size determination formula, 60 participants (40 BAPPs and 20 BAUPs) were systematically selected from University College Hospital, Ibadan (26); Adeoyo Teaching Hospital, Ibadan (6); Federal Medical Centre, Owo (8) (BAPPs); Treasure Delight International Centre, Ibadan (8) and Jesus’ Kids Autistic Centre, Ibadan (12) (BAUPs). The facilities were selected through convenience sampling. Participants’ speeches were elicited using Passage Reading Test (PRT-19), in-depth interviews (37), and participant observation (4). Participants’ speeches were audio-recorded and transcribed, and sentences were morphosyntactically analysed. The English word order and head parameters were preserved in BAPPs and in BAUPs. Lexical derivation was selectively impaired in BAPPs, whereas it was preserved in BAUPs. Also, tense and aspect were impaired in the speeches of both groups. Agreement was preserved in BAPPs but it was impaired in BAUPs. BAPPs and BAUPs both frequently omitted determiners in their speeches. While BAPPs omitted both the pronominal possessors (Pro-Gen) and nominal possessors (Nom-Gen), BAUPs correctly produced the Pro-Gen but omitted the Nom-Gen. Both BAPPs and BAUPs often omitted or substituted prepositional heads. Neither the BAPPs nor the BAUPs were able to self-generate Complementiser Phrases (CPs).The BAPPs were unable to replicate the CPs contained in the PRT whereas BAUPs replicated the base-generated complementisers. The BAUPs had difficulty with wh-movement whereas they correctly replicated wh in-situ. The syntax of non-finite constructions (PRO-inf and PRO-ing) was relatively preserved in both groups. They correctly self-generated such constructions irrespective of the position in the syntactic node, and they replicated similar structures in the PRT without difficulty. However, while the PRO-ing was unimpaired in aphasia, it was mildly impaired in autism. The BAUPs produced finite structures when presented with the PRO-ing. Morphological impairments in both conditions were characterised by omission and/or substitution of f-morphemes, while syntactic impairments were characterised by omission of lexical and functional heads, which frequently resulted in violation of the Projection Principle and Case Filter, and sometimes brought about meaning shift or loss in the participants’ speeches. The Bilingual Aphasic Patients’ and Bilingual Autistic Patients’ speeches were characterised by selective impairment, syntactic simplification and syntactic retransformation which show some preservation for the second language syntax. Avoidance of complex linguistic structures would enhance better communication.