A review of control processes and their locus in language switching

Abstract

Language switching has been one of the main tasks to investigate language control, a process that restricts bilingual language processing to the target language. In the current review, we discuss the How (i.e., mechanisms) and Where (i.e., locus of these mechanisms) of language control in language switching. As regards the mechanisms of language control, we describe several empirical markers of language switching and their relation to inhibition, as a potentially important mechanism of language control. From this overview it becomes apparent that some, but not all, markers indicate the occurrence of inhibition during language switching and, thus, language control. In a second part, we turn to the potential locus of language control and the role of different processing stages (concept level, lemma level, phonology, orthography, and outside language processing). Previous studies provide evidence for the employment of several of these processing stages during language control so that either a complex control mechanism involving different processing stages and/or multiple loci of language control have to be assumed. Based on the discussed results, several established and new theoretical avenues are considered.

Bilingual language intrusions and other speech errors in Alzheimer’s disease

“…When reading mixed-language paragraphs, particularly paragraphs written primarily in the non-dominant language, bilinguals partially inhibit the dominant language, leading dominant language targets to be replaced with non-dominant language translation equivalents more often than the reverse. Possibly similar inhibitory control processes might explain results why the dominant language sometimes exhibits larger switch-costs than the non-dominant language, though such effects might reflect transient rather than sustained control mechanisms (Bobb & Wodniecka, 2013; Declerck & Philipp, 2015a; Green, 1998; Meuter & Allport, 1999; Kroll, et al, 2008; Philipp, Gade, & Koch, 2007; Philipp & Koch, 2009). The finding of significantly reversed language-dominance effects on intrusion errors in patients but not in controls in the present study has important implications for understanding the cognitive mechanisms underlying default language selection in bilingual language production.…”

“…Full reversal of language dominance effects suggests the operation of an inhibitory control process applied to the dominant language (Gollan & Ferreira, 2009; Kroll, Bobb, Misra, & Guo, 2008), and could also imply activation of the nondominant language (to the point that its accessibility exceeds that of the typically dominant language; for reviews see Declerck & Philipps, 2015a; Runnqvist, Strijkers, Sadat, & Costa, 2011). The finding of intact reversed dominance effects in aging bilinguals with clear impairments in independent measures of nonlinguistic executive control abilities could further imply that language control mechanisms are relatively modular and specialized (Gollan & Goldrick, in press).…”

Language Control and Code-switching

“…Activation reflects control at the level of the language rather at the level of the item (see DeClerk and Philipp (2015) for discussion of the loci for language switching) 1 . Assume for present purposes that a caudate activation also tracks covert language switching.…”

Grammatical constraints on language switching: Language control is not just executive control

“…Most bilinguals have one language that is dominant i.e., relatively more proficient in many or most respects, than the other, non-dominant, language. Switch costs are often larger in the dominant language than in the non-dominant language, a result that could suggest inhibition of the dominant language when the non-dominant language is used, that must then be overcome to return to the dominant language (Meuter & Allport, 1999; for review see Declerck & Philipp, 2015b). These effects are most often attributed to inhibitory control mechanisms, specifically those that might also support non-linguistic task-switching (Green, 1998; Meuter & Allport, 1999; see also Philipp, et al, 2007; Philipp & Koch, 2009; but see Bobb & Wodniecka, 2013).…”