Aging effects on discourse production

Discourse is defined as any language “beyond the boundaries of isolated sentences” (Ultowska & Olness, 2004, p. 300), and it allows people to do things together; tease each other, build things, share feelings, and make plans for the future. Yet discourse requires more than simply generating a continuous stream of linguistic elements. Discourse production requires both within-sentence (i.e. microlinguistic) elements and processes that are traditionally associated with the field of linguistics (e.g. phonemes & syntax) as well as between-­sentence elements and processes to produce a coherent message. In this chapter, we focus on how this delicate balance between micro- and macrolinguistic processes change and are maintained within discourse as people age. To do this, we initially review the interactive-construction model of discourse. Next, we review micro- and macrolinguistic processes within aging research. For microlinguistic, we focus on lexical diversity, which can be defined as the range of vocabulary used by a person within a discourse sample. For the macrolinguistic process, we focus on coherence, which can be defined as how discourse is connected and organized beyond the grammar of a sentence. For both lexical diversity and coherence, we review common analysis techniques, what occurs to these processes as we age, and the cognitive and linguistic systems that underpin these aspects of discourse. Finally, we conclude the chapter by highlighting areas of future research within lexical diversity and coherence research that are important to understanding discourse as people age.