Bilingual experience shapes language processing: Evidence from codeswitching

Exposure-based models of language processing posit that sensitivity to distributional patterns in production can constrain the comprehension system (MacDonald, 2013; Dell & Chang, 2014). Codeswitching provides a unique circumstance to elucidate this relationship because codeswitching emerges in some bilingual communities but not in others.

This study examines the extent to which individuals’ production choices can predict comprehension difficulty in codeswitching and non-codeswitching bilingual populations. We recruited 22 Spanish-English codeswitchers in the US and 22 non-codeswitchers in Spain who were highly proficient in both languages. We focus on the comprehension and production of mixed noun phrases (mixed NPs; e.g., elM forkM). Evidence from naturalistic corpora suggests that bilinguals exhibit an overall preference for the masculine determiner (el), regardless of the noun’s gender in Spanish. In contrast, switches involving the feminine determiner (la) occur less frequently and are restricted to English nouns that are feminine in Spanish (Valdés-Kroff, 2016).

To illustrate, el-codeswitches such as (elM forkM) and (elM spoonF) are extremely common. To a lesser extent, la-codeswitches involving feminine nouns (laF spoonF) have also been attested in bilingual speech, while those involving masculine nouns (*laF forkM) have not. We predicted that electrophysiological responses would reflect this asymmetry in codeswitchers but not in non-codeswitchers. That is, while codeswitches in general should be unexpected for non-codeswitchers, only rarely-attested switches should induce processing difficulties in codeswitchers. Comprehension was examined in sentential contexts using event-related potentials where we compared different types of switches (switch vs switch) and effects of switching (switch vs no-switch); production was examined in a corpus of unscripted, task-oriented dialogues between two bilingual speakers. The same participants completed the comprehension and production experiments.

In Experiment 1, the two groups of bilinguals differed in their processing of codeswitched sentences. While non-codeswitchers were insensitive to the congruency and gender of switched target nouns (Fig. 1a, 1c), codeswitchers demonstrated an asymmetry in how they process different types of switches.

 

Specifically, codeswitchers exhibited an N400 effect to masculine targets in incongruent noun phrases, suggesting greater difficulty in lexical integration (Fig. 1b, 1d). Furthermore, we found that only non-codeswitchers displayed a switching effect in the form of an early frontal positivity for switch vs no-switch comparisons (Fig. 2a, 2c). Importantly, codeswitchers did not exhibit switch costs in conditions of the sort found in naturalistic codeswitching (Fig. 2b, 2d). This is evidenced in the lack of a switching effect in masculine congruent and feminine congruent and incongruent switching conditions.

 

To safeguard against potential language effects in the switch vs no-switch comparisons, we conducted a control experiment (Experiment 2) in which we compared electrophysiological responses to unilingual translation-equivalent sentences in English and Spanish using the same participants. Because no differences were found due to lexical characteristics of the target words in Experiment 2, we suggest that the switching effect in non-codeswitchers reflects detection of a language change during early monitoring stages of language processing (Kuipers & Thierry, 2010). In Experiment 3, participants completed a task that elicited naturally-produced codeswitched speech. Results show that proportions of noun phrase types (i.e., Spanish, English, or mixed) differed across groups: Codeswitchers produced more mixed NPs than non-codeswitchers and these switches robustly reflected the aforementioned gender asymmetry found in naturalistic codeswitching (Fig. 3).

Overall, the current study further provides evidence that individuals are highly sensitive to the constraints of their language experience, and sheds light on how production and comprehension processes are tightly linked. Our findings demonstrate how switching costs largely depend not only on the type of codeswitch but also the bilingual’s language experience.

To cite this paper:

Beatty-Martínez, A.L. & Dussias, P.E. (2017). Bilingual experience shapes language processing: Evidence from codeswitching. Journal of Memory and Language, 95, 173-189. https://doi.org/10.1016/j.jml.2017.04.002

References:

  1. MacDonald, M. C. (2013). How language production shapes language form and comprehension. Frontiers in Psychology. http://doi.org/10.3389/fpsyg.2013.00226
  2. Dell, G., & Chang, F. (2014). The P-chain: Relating sentence production and its disorders to comprehension and acquisition. Philosophical Transactions of the Royal Society B: Biological Sciences, 369, 20120394.
  3. Valdés Kroff, J. R. (2016). Mixed NPs in Spanish-English bilingual speech: Using a corpus-­based approach to inform models of sentence processing. In R. E. Guzzardo Tamargo, C. Mazak, & M. C. Parafita Cuoto (Eds.), Code‐switching in the Spanish-­speaking Caribbean and its diaspora (pp. 281–300). Amsterdam: John Benjamins.
  4. Kuipers, J. R., & Thierry, G. (2010). Event-related brain potentials reveal the time-course of language change detection in early bilinguals. NeuroImage, 50, 1633–1638