Can monolinguals be like bilinguals? Evidence from dialect switching

Bilinguals rely on cognitive control mechanisms like selective activation and inhibition of lexical entries to prevent intrusions from the non-target language. We present cross-linguistic evidence that these mechanisms also operate in bidialectals. Thirty-two native German speakers who sometimes use the Öcher Platt dialect, and thirty-two native English speakers who sometimes use the Dundonian Scots dialect completed a dialect-switching task. Naming latencies were higher for switch than for non-switch trials, and lower for cognate compared to non-cognate nouns. Switch costs were symmetrical, regardless of whether participants actively used the dialect or not. In contrast, sixteen monodialectal English speakers, who performed the dialectswitching task after being trained on the Dundonian words, showed asymmetrical switch costs with longer latencies when switching back into Standard English. These results are reminiscent of findings for balanced vs. unbalanced bilinguals, and suggest that monolingual dialect speakers can recruit control mechanisms in similar ways as bilinguals

Late Bilinguals Are Sensitive to Unique Aspects of Second Language Processing: Evidence from Clitic Pronouns Word-Order.

In two self-paced reading experiments we asked whether late, highly proficient, English-Spanish bilinguals are able to process language-specific morpho-syntactic information in their second language (L2). The processing of Spanish clitic pronouns' word order was tested in two sentential constructions. Experiment 1 showed that English-Spanish bilinguals performed similarly to Spanish-English bilinguals and revealed sensitivity to word order violations for a grammatical structure unique to the L2. Experiment 2 replicated the pattern observed for native speakers in Experiment 1 with a group of monolingual Spanish speakers, demonstrating the stability of processing clitic pronouns in the native language. Taken together, the results show that late bilinguals can process aspects of grammar that are encoded in L2-specific linguistic constructions even when the structure is relatively subtle and not affected for native speakers by the presence of a second language

Exploring the Bilingual Advantage in Executive Control: Using Goal Maintenance and Expectancies

Previous research has shown that bilingualism helps to offset age-related losses in certain executive processes such as inhibitory control, task switching and divided attention. The two studies presented in this dissertation investigated possible mechanisms underlying this bilingual advantage in executive control by examining the role of expectancies and goal maintenance in monolingual and bilingual younger (30 to 40 years) and older adults (60 to 80 years). In Chapter 2, the fadeout paradigm (Mayr & Liebscher, 2001) was used to examine differences in the ability to disengage from an irrelevant task cue. Testing began with single task blocks of shape and colour classifications presented separately, followed by a task switching block in which the two tasks alternated randomly. On trial 49, one of the tasks became irrelevant, leaving only a single task to perform. The critical variable was the point at which participants performance reflected this change by examining the number of trials required to return to single task block speed. Results showed that both younger and older bilinguals returned to single task block speeds sooner than monolinguals. The results were interpreted as showing that bilinguals were better able to use task cues to improve task performance and that outsourcing control to task cues may be beneficial. In Chapter 3, a dual modality classification paradigm was used to determine the speed at which two tasks could be executed at the same time as a means of measuring the ability to sustain task goals. The task required participants to simultaneously respond manually to visual stimuli and verbally to auditory stimuli. Results revealed that younger and older bilinguals showed smaller costs in responding to two tasks whereas monolinguals experienced larger delays in making their responses. Proportion analysis of dual task costs and pairs of responses revealed a bilingual advantage and did not show any age-related increases in costs. The results were interpreted as demonstrating the strength in goal maintenance in bilinguals, allowing them to establish a task goal, control interference from stimulus pairings in order to uphold the goal, and to manage multiple streams of information, and these abilities are sustained in aging

Immersive bilingualism reshapes the core of the brain

Bilingualism has been shown to affect the structure of the brain, including cortical regions related to language. Less is known about subcortical structures, such as the basal ganglia, which underlie speech monitoring and language selection, processes that are crucial for bilinguals, as well as other linguistic functions, such as grammatical and phonological acquisition and processing. Simultaneous bilinguals have demonstrated significant reshaping of the basal ganglia and the thalamus compared to monolinguals. However, it is not clear whether these effects are due to learning of the second language (L2) at a very young age or simply due to continuous usage of two languages. Here, we show that bilingualism-induced subcortical effects are directly related to the amount of continuous L2 usage, or L2 immersion. We found significant subcortical reshaping in non-simultaneous (or sequential) bilinguals with extensive immersion in a bilingual environment, closely mirroring the recent findings in simultaneous bilinguals. Importantly, some of these effects were positively correlated to the amount of L2 immersion. Conversely, sequential bilinguals with comparable proficiency and age of acquisition (AoA) but limited immersion did not show similar effects. Our results provide structural evidence to suggestions that L2 acquisition continuously occurs in an immersive environment, and is expressed as dynamic reshaping of the core of the brain. These findings propose that second language learning in the brain is a dynamic procedure which depends on active and continuous L2 usage

Performance difference in verbal fluency in bilingual and monolingual speakers

Research has shown that bilinguals can perform similarly, better or poorly on verbal fluency task compared to monolinguals. Verbal fluency data for semantic (animals, fruits and vegetables, and clothing) and letter fluency (F, A, S) were collected from 25 Bengali-English bilinguals and 25 English monolinguals in English. The groups were matched for receptive vocabulary, age, education and non-verbal intelligence. We used a wide range of measures to characterize fluency performance: number of correct, fluency difference score, time-course analysis (1st RT, Sub-RT, initiation, slope), clustering, and switching. Participants completed three executive control measures tapping into inhibitory control, mental-set shifting and working memory. Differences between the groups were significant when executive control demands were higher such as number of correct responses in letter fluency, fluency difference score, Sub-RT, slope and cluster size for letter fluency, such that bilinguals outperform the monolinguals. Stroop performance correlated positively with the slope only for the bilinguals

Bilingualism Across the Adult Life-Span: Age and Language Usage Are Continuous Variables

The purpose of this dissertation research was to analyze the effects of bilingualism and age on cognitive function. Specifically, I investigated the impact of bilingualism and age on two measures of executive control. The Stroop task is a measure of response inhibition, and the Flanker task is a measure of attention selection. Participants responded using a computer mouse. The mouse-tracking paradigm allowed me to examine the continuous dynamics of the responses as participants completed each trial. A better understanding of the impact of bilingualism and age on cognitive function has the potential to minimize cognitive decline in older age. The results showed that younger age was associated with better cognitive function in both tasks, but the positive effect of bilingualism was limited to the Stroop task. In response inhibition, the detrimental effect of age can be curtailed by the positive effect of bilingualism. Bilingualism offset approximately 60% of age-related cognitive decline in the current study. These results provide further support for the notion that bilingualism is one way of enhancing some aspects of cognitive function across the lifespan. The present study adds to the literature by studying these effects without dichotomizing bilingualism or age. It is important to measure continuous variables as such; varying degrees of the same construct have the potential to result in different levels of executive function