A Comparison Between First and Second Language Generative Discourse Production in Bilingual Persons With Mild Dementia

Purpose: With the increasing prevalence of dementia, quantifying the relationships between languages in discourse expression for bilingual speakers provides valuable insight into the impact of bilingualism on language discourse expression. The purpose of the study was to compare expository discourse in first language (L1; Kannada) and second language (L2; English) of healthy elderly adults (HEA) and persons with mild dementia (PWMD). Method: Nine bilingual PWMD and 10 bilingual age-matched HEA with vocational proficiency in L1 and L2 participated in the study. Discourse samples were gathered from each participant, transcribed verbatim, and segmented into the four related T-unit variables: content (number of T-units, number of clauses per T-unit), complexity (number of words per T-unit), and relevance (number of incomplete and irrelevant T-unit). T-unit scores were statistically analyzed between their L1 and L2 using one-way analysis of variance. Results: There were statistically significant differences between groups, with HEA producing more content, complexity, and relevance than PWMD. Furthermore, within HEA, significantly more content was produced in L1. However, there were no statistically significant differences in T-units between L1 and L2 within the PWMD group. Conclusions: There is a general pattern of decline in discourse production in PWMD compared with HEA in both L1 and L2. While the healthy adults demonstrated a clear dominance in their L1, this was not evident in PWMD. Within the PWMD groups, L1 and L2 were found to decline at the same pace. Therefore, when evaluating bilingual PWMD, assessing their discourse in either their L1 or L2 is appropriate.