The Left, The Better: White-Matter Brain Integrity Predicts Foreign Language Imitation Ability

Area of Science:

• Neuroscience
• Linguistics
• Speech Science

Background:

• Speech imitation is vital for acquiring native and foreign languages.
• Significant individual variations exist in foreign language sound imitation ability.
• The underlying reasons for these differences, possibly structural predispositions, are not fully understood.

Purpose of the Study:

• To investigate the relationship between white-matter structural properties of the arcuate fasciculus (AF) and foreign language imitation performance.
• To identify specific AF regions associated with second-language learning aptitude.

Main Methods:

• Diffusion tensor imaging (DTI) tractography was used to analyze the AF in 52 German speakers.
• Both manual and automatic reconstruction methods were employed to examine AF structural properties.
• Participants completed a Hindi sentence- and word-imitation task.

Main Results:

• A greater leftward lateralization of AF volume correlated with better Hindi imitation performance.
• Higher fractional anisotropy (FA) values in the anterior left AF were associated with improved imitation skills.
• Both manual and automatic DTI analyses revealed a left-lateralization trend linked to imitation aptitude.

Conclusions:

• White-matter structure, specifically leftward asymmetry in the AF, plays a role in foreign language imitation ability.
• This study provides novel insights into the neural underpinnings of second-language learning aptitude.
• The findings highlight the potential of DTI tractography in understanding individual differences in language learning.