Tapping into neural resources of communication: formulaic language in aphasia therapy.

Abstract

Decades of research highlight the importance of formulaic expressions in everyday spoken language (Vihman, 1982; Wray, 2002; Kuiper, 2009). Along with idioms, expletives, and proverbs, this linguistic category includes conversational speech formulas, such as “You've got to be kidding,” “Excuse me?” or “Hang on a minute” (Fillmore, 1979; Pawley and Syder, 1983; Schegloff, 1988). In their modern conception, formulaic expressions differ from newly created, grammatical utterances in that they are fixed in form, often non-literal in meaning with attitudinal nuances, and closely related to communicative-pragmatic context (Van Lancker Sidtis and Rallon, 2004). Although the proportion of formulaic expressions to spoken language varies with type of measure and discourse, these utterances are widely regarded as crucial in determining the success of social interaction in many communicative aspects of daily life (Van Lancker Sidtis, 2010). The unique role of formulaic expressions in spoken language is reflected at the level of their functional neuroanatomy. While left perisylvian areas of the brain support primarily propositional, grammatical utterances, the processing of conversational speech formulas was found to engage, in particular, right-hemisphere cortical areas and the bilateral basal ganglia (Hughlings-Jackson, 1878; Graves and Landis, 1985; Speedie et al., 1993; Van Lancker Sidtis and Postman, 2006; Sidtis et al., 2009; Van Lancker Sidtis et al., 2015). It is worth pointing out that parts of these neural networks are intact in left-hemisphere stroke patients, leading to the intriguing observation that individuals with classical speech and language disorders are often able to communicate comparably well based on a repertoire of formulaic expressions (McElduff and Drummond, 1991; Lum and Ellis, 1994; Stahl et al., 2011). An upper limit of such expressions has not yet been identified, with some estimates reaching into the hundreds of thousands (Jackendoff, 1995). The above literature suggests that formulaic expressions may be viewed as a valuable resource in speech-language therapy. However, surprisingly little is known about their potential impact on the success of popular programs in clinical rehabilitation. The current opinion paper seeks to address this matter by outlining the contribution of formulaic expressions to seminal approaches in recovery from speech and language disorders after stroke.