With National Science Foundation support, Ms. Rhonda McClain will collect data for her doctoral dissertation under the direction of Dr. Judith Kroll and Dr. Eleonora Rossi. Speaking fluently in a second language is a notoriously difficult skill to develop as a late learner, presumably because the second language competes for selection with the native language. Current research demonstrates that bilinguals experience persistent activation of both languages even when speaking one language alone. A critical question is how bilinguals prevent speaking the more dominant or native language when trying to speak the second language. Recent studies have reported that the native language becomes inhibited, or suppressed, in order to speak in the second language. However, little is known about what type of information becomes inhibited in the native language. One possibility is that all of the words in one language are suppressed. Alternatively, a network of words that bear resemblance in meaning to each other become active or inhibited together. Another possibility is that specific words that had been spoken in the other language are inhibited. It is also unclear whether inhibition is momentary or long lasting. The planned experiments will test the scope of inhibition (what is inhibited) its time course (the duration of inhibition) by using electrophysiological measures that may provide a more sensitive index of the earliest moments of speech planning. A comparison of bilinguals and monolinguals will also determine whether the repeated requirement for bilinguals to inhibit their native or more dominant language confers expertise in the realm of inhibitory control relative to monolingual speakers.
The funded research has a number of broader implications. It will contribute important foundational knowledge about multilingualism that will inform educational issues in a society in which many learners are faced with the task of acquiring a second language past the earliest stages of childhood and at risk for academic failure unless they acquire the second language rapidly. The inhibitory processes that are the target of the planned investigation hold implications for better understanding the ability of bilinguals to maintain the two languages under conditions that may support the use of only one language. The research will also contribute to the training of an increasingly diverse group of language scientists by including undergraduate research students who are themselves bilingual.
Adult second language learners are notoriously poor at speaking their later learned language, often omitting words, producing errors, or speaking in a generally disfluent manner. A chief reason for these limitations is that whenever learners attempt to speak their second language, their more dominant native language is activated in parallel. Although there is virtually no research evidence on the speech processes of adult second language learners, evidence suggests that proficient bilinguals experience parallel activation of words in their dominant and second language during speech planning. However, despite parallel activation of two languages and potential competition between them, proficient bilinguals rarely produce errors or cross-language confusions during speech production. This suggest that bilinguals develop a means for negotiating the presence of the dominant language during second language production. Not only does this expertise in negotiating competition benefit speech production, but recent research discoveries suggest that this expertise generalizes beyond language to impact general cognitive efficiency. This project was designed to examine how learners negotiate the activation of the more dominant native language when they must produce their second language. A second question investigated in this project was whether second language learners demonstrate advantages in cognitive efficiency that generalize beyond language when their performance is compared to monolinguals who do not speak more than one language. The first experiment was designed to examine whether second language learners exploit inhibition during speech production as a means of regulating their dominant language. The main hypothesis explored in this experiment, was that inhibition would be critical for speaking the second language. Due to learners’ limited ability to speak their second language, a novel picture naming task was used in which we focused on the consequences of attempting to speak the second language on the dominant native language. Because learners were expected to speak their dominant language with little to no disruptions, and decreases in the efficiency of dominant language after speaking the second language would suggest inhibition. Another novel aspect of this research is that during the picture naming task the electrical activity from the subjects’ brains (called event-related potentials, or ERPs) was measured. In addition to overt speech production measures (such as the time taken to speak the name of the pictures), this brain measure provided a way to examine evidence for inhibition. The results of this study showed that there were subtle changes to the dominant language as a consequence of attempting to speak their second language that were observable in the overt speech production measure and no evidence of inhibition in the brain measure. This evidence suggests that learners use other, non-inhibitory means to regulate the dominant language when attempting to speak their second language. A second hypothesis that was tested in the first experiment, asked whether second language learners demonstrate differences in speech production when preparing to speak just their dominant language. An assumption is that inhibition would generalize beyond the immediate requirement to speak the second language, to cases in which learners must plan speech generally. To test this hypothesis, a group of second language learners named pictures only in their dominant language and their performance was compared to monolinguals. Second language learners differed from monolinguals, but did not show evidence of inhibition. Rather, their performance indicated that they were advantaged relative to monolinguals in naming pictures entirely in their dominant language. To the best of our knowledge, this is one of the few studies to report an advantage for bilinguals in speech production relative to monolinguals. The second experiment investigated potential differences in the ability to engage inhibitory control between monolinguals and second language learners. Second language learners and monolinguals performed a picture naming task in which they were cued to name in a go/no-go fashion. Go pictures were displayed with a cue that signaled pictures were to be named overtly and no-go pictures were displayed with a cue that signaled the picture should not be named. Generally, when brain waves are monitored as individuals perform a go/no-task no-go conditions the ERPs show evidence of inhibition. The results of the second experiments showed that inhibition was more clearly evident in second language learners compared to monolinguals, even though both groups showed comparable performance in their overt naming. This suggests that second language learners’ brains may be specially tuned for inhibitory processing as a function of their learning experience. This research contributes to our understanding of plasticity within and outside of language. When second language learners plan speech, they differ from monolinguals. Some patterns that were observed in this study suggest learners are advantaged in speech production, whereas others suggest they experience costs. These patterns appear to be impacted by the language context that bilinguals are asked to speak in. A promising line of future research will examine the consequences of language contexts for language and cognition.
