The use of discourse particles in oral picture description by individuals with primary progressive aphasia

Discourse production, including the use of discourse particles, is crucial in everyday communication. Discourse particles (e.g., ja ‘yeah’) form a heterogeneous group of words that fulfil different functions such as structuring the discourse or marking the relationship between the hearer and speaker. Primary progressive aphasia (PPA) is a neurodegenerative language condition that causes communication breakdowns. In this study, we examined the production of discourse particles by 58 Dutch-speaking individuals with PPA and 40 neurologically healthy speakers (NHS). We analysed language samples obtained from a picture description task for the use of discourse particles, comprising both discourse particles that require an assessment of the interlocutor's discourse belief (e.g., eigenlijk ‘actually’) as well as discourse particles with a more general discourse-structuring function (e.g., ja ‘yeah’ nee ‘no’, nou ‘well’). We found that individuals with PPA used the discourse particle ja 'yeah' more frequently than NHS (p < .001) relative to eigenlijk. The results also showed that the discourse particles nee ‘no’ and nou ‘well’ were used differently by individuals with PPA versus NHS. These discourse particles were employed by individuals with PPA to signal or manage word-finding difficulties. The findings underline the variety in functions and complexity of discourse markers. Studying and comparing the use of individual particles by speakers with a neurodegenerative language disorder is therefore not only informative to understand these disorders but also provides more insight into the heterogeneity of the class of discourse particles.