Bilingual language processing: A meta-analysis of functional neuroimaging studies

Abstract

Notwithstanding rising interest, a coherent picture of the brain's representation of two languages has not yet been achieved. In the present meta-analysis we analysed a large number of functional neuroimaging studies focusing on language processing in bilinguals. We used activation likelihood estimation (ALE) to enucleate activation areas involved in bilingual processing and control of different types of linguistic knowledge -lexico-semantics, grammar, phonology -in L1 and L2. Results show that surprisingly, compared to L2, lexico-semantic processing in L1 involves a widespread system of cortico-subcortical regions, especially when L2 is acquired later in life. By contrast, L2 processing recruits regions exceeding the L1 semantic network and relating to executive control processes. Only few regions displayed selective activation for grammar and phonology. Analyses of language switching highlight a functional overlap between domain-general and bilingual language control networks. Collectively, our findings point to a shared neural network for L1 and L2 with few differences depending on the linguistic level. The emerging picture identifies under-investigated issues, offering clear directions for future research.

On the phantom-like appearance of bilingualism effects on neurocognition: (How) should we proceed?

“…Moreover, being bilingual is not a static characteristic or an ‘on/off’ experience. As we have noted, recent research indicates that when one considers bilingualism as the spectrum of dynamic experiences it is, multiple variables are shown to affect the occurrence and degree of cognitive and neuroanatomical adaptations (e.g., Bak, 2016b; Bialystok, 2016; Luk & Bialystok, 2013; Li et al, 2014; De Cat, Gusnanto & Serratrice, 2018; Gullifer et al, 2018; Dash et al, 2019; Beatty-Martínez et al, 2019; DeLuca et al, 2019; 2020; Sulpizio, Del Maschio, Fedeli & Abutalebi, 2020b). The elusiveness of bilingual effects, then, could be related, at least partially, to the polysemous nature of the term ‘bilingual’, referring to very different populations across studies.…”

Neural Evidence of Language Membership Control in Bilingual Word Recognition: An fMRI Study of Cognate Processing in Chinese–Japanese Bilinguals

“…(word identification system), and the SMA [−6, 20, 49] (task/decision system), as defined by recent studies (Hsieh et al, 2017;Sulpizio et al, 2020). Activation patterns were further extracted to compare cognitive processing for each word type (Figure 4).…”

Effect of Picture-Book Reading With Additive Audio on Bilingual Preschoolers’ Prefrontal Activation: A Naturalistic Functional Near-Infrared Spectroscopy Study

“…More precisely, longer sentences or a more complex auditory story might generate more MFG brain activation in the process of comprehending the English story. In a recent study, Sulpizio et al (2020b) found that the larger involvement of dorsal-stream PFC resources in difficult rather than easy conditions could be related to the additional demands of phonological computation and cognitive decoding in L2. Thus, the more difficult auditory story engaged more brain networks for language processing and cognitive processing, to a certain extent.…”