The Effect of Mental Illness on Language Regression to the Mother Tongue in Bilingual Teenagers

Affective disorders in children and adolescents could impair the acquisition of a second language in bilingual individuals. The acute exacerbation of a preexisting mental illness may also lead to a loss of the ability to speak the second language for a period of time and the regression to the first (native) language as the only mode of communication. The effect could be lasting since the second language seems to have a critical period of optimal acquisition and proficiency. The underlying neural mechanisms indicated that the second language was more vulnerable to the effects of mental illness than the native language.