Neural and Behavioural Correlates in Adults with Exposure to a Third Language

Abstract

Aim: The study aimed to explore the neural and behavioural correlates of third language (Kannada) proficiency among native Malayalam speaking adults. Method: A total of 10 native Malayalam speakers with high proficiency in Kannada and another 10 with low proficiency in Kannada were recruited for the study. The following measures were carried out for both the groups - speech perception in noise testing with two types of noise – speech noise and Kannada speech babble, cognitive effort assessment for speech perception in the two noise conditions and FFR recording in quiet and noise conditions. Result: The results of the study showed that the speech perception scores in the presence of speech noise and Kannada speech babble were higher for the low proficiency group though not significantly. The low proficiency group tended to have higher SIS scores in the presence of speech noise compared to speech babble. However, there was no significant difference in speech perception performance across the two noise conditions for the high proficiency group. The FFR F0 amplitudes in quiet and noise were larger for the high proficiency group, though not significantly. A comparison of cognitive effort required for speech perception across the two noise conditions revealed no significant differences between the groups. However, both the groups required higher cognitive effort for speech perception in babble compared to in speech noise. In the high proficiency group, a significant positive correlation was present between FFR F0 amplitude in quiet and in noise. In the low proficiency group, a significant negative correlation was present between FFR F0 amplitude in noise and SIS scores in speech noise. The FFR F0 amplitude was positively correlated with cognitive effort for speech perception in speech noise in the low proficiency group. L3 proficiency was negatively correlated with cognitive effort for speech perception in both speech noise and Kannada speech babble conditions in the low proficiency group. The low proficiency group also showed a significant positive correlation between cognitive effort for the two noise conditions during speech perception testing. Conclusion: The results of the study suggest that while extensive third-language exposure contributing to higher levels of proficiency in the third language enhances subcortical pitch encoding (as evidenced by larger FFR F0 in quiet and noise), it does not by itself yield superior speech-in-noise scores when compared across groups.