International Conference on Auditory Cortex. 2017.09.10-15. Banff, Canada

THE EFFECT OF BILINGUALISM ON SYNTACTIC AND SEMANTIC RECOGNITION IN CHILDREN

Delgertsetseg. Ch, Nyamsuren. D and Chuluundorj. B Brain Research Laboratory, University of the Humanities, Ulaanbaatar, Mongolia

ABSTRACT

Introduction: Bilingualism is beneficial in development of cognitive function in children. The benefits are not limited to improvements in social communication skills, sensitivity to language structures, details, grammar, conflict solving, creativity, analogical reasoning, classification, cognitive flexibility, inhibition and dementia prevention. However, bilingualism effect on cognitive processing of syntactic and semantic violations is not well understood yet. This study aimed to determine the effect of bilingualism on event related potentials (ERP) during semantic and syntactic violation tasks in children and adolescents. Methods: 76 Mongolian native speakers were randomly selected from Ulaanbaatar city, Mongolia. From them, 36 subjects were bilinguals and 40 were monolinguals (control group), 58% female and 42% male, aged 3-21. Half of the subjects had semantic tasks and half - syntactic. Among 36 bilinguals, 26 were Mongolian-English and 10 were Mongolian-Russian bilinguals. Visual and auditory stimuli were presented to the subjects in pictures, followed by Mongolian sentences one word per time. Auditory stimuli (22 Hz, 60 dB) were recorded in acoustically shielded room by female native speaker 1 word every 2 seconds. Half of the sentences had syntactically or semantically incongruent words and half – congruent words. In semantic tasks the target words were either nouns, verbs or adjectives. The subjects had 64 trials, 3 seconds per one word stimulus. Brain electric waves were measured during the task presentations by using WEEG32 recording Laxtha Inc., Korea) and 21 electrode caps (Electro-cap Inc., USA). The following programs were used for recording and analyzing of the waves: Telescan (Laxtha Inc., Korea), Matlab 2017 (Mathworks Inc., USA), ICA on EEGlab (UCSD, USA), ERPlab (Github Inc., USA), GraphPad Prism (GraphPad software Inc., USA). Results : In experiments with semantic violation tasks, N400, P300 and P600 are known to be important ERP peaks in semantic tasks and averages of their amplitude and latency were assessed after an onset of stimuli within 350-450, 250-350 and 500-800 millisecond (ms) intervals accordingly. This study showed that mono- and bilinguals had significant differences in the electrophysiological analysis of these peaks. Bilingual brain spends significantly lower efforts for processing of semantically incongruent words than monolinguals, but with a same processing speed in terms of N400, P300 and P600. Semantically incongruent words activate a dominant brain hemisphere with differences between mono- and bilinguals. While N400, P300 and P600 were mainly elicited in parietal and occipital sites in monolinguals, in bilinguals they had frontal and parietal involvement. Age of bilinguals and initiation period of their second language study (L2 onset) significantly affected latency, but not the location and power of brain activation. For instance, N400 latency was significantly lower when bilinguals initiated L2 earlier in life well before age 9. Length of L2 exposure (L2 duration) affected only P300 latency and lower latency was associated with longer L2 duration, i.e. 9-13 years. Additionally L2 types (English and Russian) did not affect the ERP results in semantic tasks. In experiments with syntactic violation tasks, the ERP peaks such as ELAN, N400 and P600 are known to be elicited during syntactic tasks and were assessed after the onset of stimuli in the range of 150-250, 350-450 and 500-800 ms accordingly. Similarly to the semantic tasks, in syntactic tasks peak amplitudes were also significantly lower in bilinguals than in monolinguals. Age of the subjects and L2 onset period, but not L2 duration and type, significantly affected expression of ELAN, N400 and P600. Thus, amplitude of peak effects was significantly lower in bilinguals than in monolinguals at their ages 3-6 especially in frontal positions.

Conclusion: Bilingualism is beneficial in cognitive processing of semantic and syntactic tasks in native language. Main benefits can be observed when bilinguals are exposed to their second language earlier in their lives.

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Delgertsetseg Chuluundorj, Nyamsuren Dorjpalam and Chuluundorj BegzBrain Research Laboratory, University of the Humanities, Ulaanbaatar, Mongolia

Sponsors:International Conference on Auditory Cortex. 2017.09.10 -15. Banff, Canada

THE EFFECT OF BILINGUALISM ON SYNTACTIC AND SEMANTIC RECOGNITION IN CHILDREN

INTRODUCTION

Bilingualism is beneficial in development of cognitive function in children. The benefits are not limited to improvements in socialcommunication skills, sensitivity to language structures, details, grammar, conflict solving, creativity, analogical reasoning,classification, cognitive flexibility, inhibition and dementia prevention. However, bilingualism effect on cognitive processing ofsyntactic and semantic violations is not well understood yet.

AIM

To determine the effect of bilingualism on event related potentials (ERP) during semantic and syntactic violation tasks in childrenand adolescents.

METHODS

76 Mongolian native speakers were randomly selected from Ulaanbaatar city, Mongolia. From them, 36 subjects were bilingualsand 40 were monolinguals (control group), 58% female and 42% male, aged 3-21. Half of the subjects had semantic tasks and half -syntactic. Among 36 bilinguals, 26 were Mongolian-English and 10 were Mongolian-Russian bilinguals.Visual and auditory stimuli were presented to the subjects in pictures, followed by Mongolian sentences one word per time.Auditory stimuli (22 Hz, 60 dB) were recorded in acoustically shielded room by female native speaker 1 word every 2 seconds. Halfof the sentences had syntactically or semantically incongruent words and half – congruent words. In semantic tasks the targetwords were either nouns, verbs or adjectives. The subjects had 64 trials, 3 seconds per one word stimulus. Brain electric waveswere measured during the task presentations by using WEEG32 recording Laxtha Inc., Korea) and 21 electrode caps (Electro-capInc., USA) (Figure 1). The following programs were used for recording and analyzing of the waves: Telescan (Laxtha Inc., Korea),Matlab 2017 (Mathworks Inc., USA), ICA on EEGlab (UCSD, USA), ERPlab (Github Inc., USA), GraphPad Prism (GraphPad softwareInc., USA).

Figure 1. A schematic picture of 21 electrode placement sites on the scalp accordingto 10-20 international system.

RESULTS

Study 1. Semantic violation tasks

N400, P300 and P600 are known to be important ERP peaks in semantic tasks and averages of their amplitude and latency wereassessed after an onset of stimuli within 350-450, 250-350 and 500-800 millisecond (ms) intervals accordingly (Figure 2). Thisstudy showed that mono- and bilinguals had significant differences in the electrophysiological analysis of these peaks. Bilingualbrain spends significantly lower efforts for processing of semantically incongruent words than monolinguals, but with a sameprocessing speed in terms of N400, P300 and P600 (Figures 3 and 4).

a) b)

Figure 2. Wave plots show average of ERP waves in monolinguals and bilinguals during semantic tasks. The ERPs were recordedduring semantic tasks with congruent sentences and incongruent nouns, verbs and adjectives combined in: a) monolinguals,b) bilinguals. X axis shows time after word onset in milliseconds. Y axis shows amplitude in microvolts.

N400 P300 P600

Figure 3. Peak amplitudes of ERP effects in semantically incongruent tasks in bilinguals and monolinguals (ms). Mann-Whitneytwo-tailed t test. ****P<0.0001.

N400 P300 P600

Figure 4. Peak latencies of ERP effects in semantically incongruent tasks in bilinguals and monolinguals (ms).

Semantically incongruent words activate a dominant brain hemisphere with differences between mono- and bilinguals. WhileN400, P300 and P600 were mainly elicited in parietal and occipital sites in monolinguals, in bilinguals they had frontal and parietalinvolvement (Figure 5). Age of bilinguals (Figure 6a) and initiation period of their second language study (L2 onset) significantlyaffected latency, but not the location and power of brain activation. For instance, N400 latency was significantly lower whenbilinguals initiated L2 earlier in life well before age 9 (Figure 6b). Length of L2 exposure (L2 duration) affected only P300 latencyand lower latency was associated with longer L2 duration, i.e. 9-13 years. Additionally L2 types (English and Russian) did not affectthe ERP results in semantic tasks (data not shown).

N400 P300 P600 a) N400 P300 P600

b) N400 P300 P600

Figure 5. Topoplots showing N400,

P300 and P600 effects in incongruent

semantics tasks. Shown are averages of Figure 6. Peak latencies (ms) of N400, P300 and P600 in different age groups and

peaks in the range of 350-450, 250-350 L2 onset ages in monolinguals (grey color) and bilinguals (black color). One way

and 500-800 ms. ANOVA with Fisher’s LSD test. *P<0.05, **P<0.01.

Study 2. Syntactic violation tasks

The ERP peaks such as ELAN, N400 and P600 are known to be elicited during syntactic tasks and were assessed after the onset ofstimuli in the range of 150-250, 350-450 and 500-800 ms accordingly (Figure 7). Similarly to the semantic tasks, in syntactic taskspeak amplitudes were also significantly lower in bilinguals than in monolinguals (data not shown). Age of the subjects and L2onset period, but not L2 duration and type, significantly affected expression of ELAN, N400 and P600. Thus, amplitude of peakeffects was significantly lower in bilinguals than in monolinguals at their ages 3-6 especially in frontal positions (Figure 8).

a) b)

Figure 7. Wave plots show average of ERP waves in monolinguals and bilinguals during syntactic tasks with congruent orincongruent words in: a) monolinguals, b) bilinguals. X axis shows time in milliseconds. Y axis shows amplitude in microvolts.

ELAN N400 P600a)

b)

Figure 8. Peak amplitudes of ERP effects in syntactically incongruent tasks in bilinguals and monolinguals in different age groups(µV): a) in left, b) in right frontal electrode sites. One way ANOVA was used. *P<0.05’ **P<0.01, ***P<0.001, ****P<0.0001.

CONCLUSION

Bilingualism is beneficial in cognitive processing of semantic and syntactic tasks in native language. Main benefits can beobserved when bilinguals are exposed to their second language earlier in their lives.

ACKNOWLEDGMENTS

We would like to acknowledge the Mongolian Foundation for Science and Technology and University of the Humanities forsponsoring this work, E. Khongorjin for her technical assistance and all our volunteers and their families for time and support.