Demands on executive functioning can differ among monolinguals: switch cost profiles in balanced vs. unbalanced bidialectal speakers

One potential reason behind failures to replicate a bilingual advantage in executive functioning maybe associated with different demands on inhibitory control among speakers considered to be monolingual (Kirk et al, 2014). Specifically, in many parts of the world, speakers are fluent in several linguistic varieties, and often switch between these varieties freely. For example, in situations of diglossia, speakers use a regional variety alongside a standard ‘high’ variety of their native language;however these varieties are not considered separate languages, nor are their speakers considered bilingual. To investigate whether these similar varieties are represented as different linguistic systems we adapted the language switching paradigm (Meuter & Allport, 1999) for use with bidialectal speakers of Standard Scottish English (SSE) and Dundonian, a regional dialect of Scots. We tested participants who routinely switch between SSE and Dundonian in everyday life (‘active users’), participants with passive knowledge of Dundonian who reported only using SSE in everyday life (‘passive users’), alongside participants who spoke Standard Anglo-English and only reported cursory exposure to Dundonian (‘non-users’). Self-reports were corroborated by expert ratings of authenticity of Dundonian pronunciation, which did not differ between active and passive users but was significantly worse for non-users. Participants were cued to name pictures either in Standard English or in Dundonian. Half of the picture names were cognates differing only in pronunciation (e.g.‘house’ vs. ‘hoose’); the rest were non cognates (e.g. ‘hill’ vs. ‘brae’). We found symmetrical switch costs in both active and passive users, which were larger for non-cognates than for cognates. In contrast, non-users displayed significant asymmetrical switch costs thus resembling the pattern of results found for non-balanced bilinguals (Costa & Santesteban, 2004). These findings highlight the importance of considering use of different linguistic varieties within monolinguals when theorizing about what demands language use may impose on executive functioning.