Answer: Theses cognitive benefits of speaking multiple languages occurs as a result of LANGUAGE CO-ACTIVATION.
Explanation:
Language co-activation is the process whereby a bilingual or multilingual individual's brain even when using one language maintains the active parts of the brain associated with the other language/languages. For example, an English & French speaking lady even while speaking French, her brain would still maintain the active parts of her English language.
Language co-activation has the benefits of higher rate of sensory perception leading to improved brain structure. The process of language co-activation is automatic leading the brain being able to perform complex processes and reduce likelihood of experiencing dementia.