Diglossia in Arabic refers to the existence of two distinct varieties: Spoken Arabic (SA), which is used orally in daily communication, and literary Arabic (LA), used in reading, writing, and for formal functions. Similarly, bilinguals often use different languages (L1, L2) for different purposes, so the question presents itself: Is Arabic diglossia a type of bilingualism? Because behavioral and fMRI studies provide contradictory answers, the current paper develops a cognitive account grounded i...