The bilingual brain
An Introduction to Bilingualism: Principles and Processes, Second Edition
The brain is a dynamic system-it is shaped by everything we do, perceive, or otherwise experience. In particular, brain structure and function are heavily affected by acquiring a skill through frequent practice and feedback. Neurobiologists have documented changes in the brain that result from skill acquisition such as the ability to play an instrument, chess, and video games. Managing two languages, a skill often acquired early during development, is arguably one of the most frequently engaged skills in daily life and over a lifetime. As such, bilingualism is a well-studied skill that is known to affect both brain structure and function.
Blackburn, Angélique M., "The bilingual brain" (2018). Psychology & Communication Faculty Publications. 7.