A neurophysiological study of noun-adjective agreement in Arabic: The impact of animacy and diglossia on the dynamics of language processing

We used event-related brain potentials to identify the neurophysiological responses of Arabic speakers to processing full and deflected agreement in plural noun-adjective constructions in Standard Arabic. Under full agreement, an adjective fully agrees in number and gender with a preceding plural noun, but only when this noun is human, while it is systematically marked feminine singular when the noun is non-human under deflected agreement. We recorded grammaticality judgment and ERP responses from 32 speakers of Arabic to sentences violating full and deflected agreement and their well-formed counterparts. The participants were relatively fast and accurate in judging all the sentences, although violations, especially deflected agreement violations, were not always deemed ungrammatical. However, the ERP responses show a differential processing of human versus non-human violations. Violations of full agreement involving human nouns elicited larger N400 and P600 components than violations of deflected agreement involving non-human nouns, whose ERP signatures were hardly distinguishable from those of their acceptable counterparts. Our results present evidence for animacy (more specifically, humanness) and inter-dialect effects on language processing. We argue that violations of Standard Arabic deflected agreement are not treated as outright violations because non-human referents permit both full and deflected agreement in Spoken Arabic. We discuss these results in light of the ERP literature on agreement processing and the role of animacy/humanness in grammar, and highlight the potential effect of diglossia on the architecture of the mental grammar of Arabic speakers.