Language pathology across different languages
Agrammatic aphasia (AA) and Specific Language Impairment (SLI) are both characterised by verb processing difficulties. A related function of this deficit is the so-called verb argument structure, i.e. type and number of complements selected by verbs. For example, the verbs ´to sleep´ and ´to build´ are intransitive and transitive and select one and two arguments, respectively – ´sleep´ one subject and ´build´ a subject and an object. There is a need to better understand whether argument structure complexity increases lexical or morphosyntactic difficulties. Contrasting French and Spanish with Basque, a language isolate rarely studied in the context of language pathology, can help shed light on this issue. Against this background, the project CCVP (Cross-linguistic and Cross-population Verb Processing) is assessing verb argument structure complexity effects in Basque, in which verb agrees overtly with subject, direct and indirect objects and which contrasts with French and Spanish, in which verb agrees overtly with subject only. Other questions include whether these processing difficulties affect both production and comprehension of language and if errors are specific to verb processing. Research to date has broadened the knowledge base on verb deficits in SLI and AA with regard to argument structure. The project has conceptualised a test, and for its optimisation identified and created stimuli that experts have qualified as accurate and usable across the entire Basque region. Language-specific properties are being taken into account when creating a test in different languages. A novel approach to the development of a comprehension task, which takes advantage of the pro-drop feature, has been well received and deemed relevant for assessing verb morphosyntactic decoding. The same holds for the collection of Basque, French and Spanish data from bilinguals to define how an individual manifests the same underlying deficit in structurally different languages. The test has been developed into an application, useful for speech and language therapists and researchers. To date, the project has assessed 30 adults, 30 children (aged 5-10), 3 adults with AA, 5 adults with other aphasia types, and 18 children with SLI. Among the participants, 30 were French monolingual native speakers; 28 were Basque-Spanish bilingual native speakers and 28 Spanish monolingual native speakers. More children with SLI and adults with aphasia will be assessed using the test. Preliminary data have been presented at international conferences and workshops, and work has begun on a co-authored paper on argument structure and verb deficits in French SLI. CCVP is contributing to knowledge on impaired versus normal verb processing in three languages with distinct morphological properties. The outcomes will be especially interesting for research into the neuropsychological bases of human grammar in general, and verb processing in particular.
Keywords
Language pathology, Basque, agrammatic aphasia, Specific Language Impairment, verb processing, cross-linguistic
