Multilingualism and acquired neurogenic speech disorders

Acquired neurogenic communication disorders can affect language, speech, or both. Although neurogenic speech disorders have been researched for a considerable time, much of this work has been restricted to a few languages (mainly English, with German, French, Japanese and Chinese also represented). Further, the work has concentrated on monolingual speakers. In this account, I aim to outline the main acquired speech disorders, and give examples of research into multilingual aspects of this topic. The various types of acquired neurogenic speech disorders support a tripartite analysis of normal speech production. Dysarthria (of varying sub-types) is a disorder of the neural pathways and muscle activity: the implementation of the motor plans for speech. Apraxia of speech on the other hand is a disorder of compilation of those motor plans (seen through the fact that novel utterances are disordered, while often formulaic utterances are not). Aphasia (at least when it affects speech rather than just language) manifests as a disorder at the phonological level; for example, paraphasias disrupt the normal ordering of segments, and jargon aphasias affect both speech sound inventories and the link between sound and meaning. I will illustrate examples of various acquired neurogenic speech disorders in multilingual speakers drawn from recent literature. We will conclude by considering an example of jargon aphasia produced by a previously bilingual speaker (that is, bilingual before the acquired neurological damage). This example consists of non-perseverative non-word jargon, produced by a Louisiana French-English bilingual woman with aphasia. The client’s jargon has internal systematicity and these systematic properties show overlaps with both the French and English phonological system and structure. Therefore, while she does not have access to the lexicon of either language, it would seem that she accesses both the French and English phonological systems.