This volume provides a collection of studies representing diversity and innovation in Arabic linguistics. The volume includes several papers authored by leaders in the field organized around key aspects of Arabic morphosyntax, semantics, phonology, and sociolinguistics, as well as language acquisition and neurolinguistics. Balancing depth and width of coverage, the volume integrates a variety of papers associated with inherent dialectal and diglossic variation, innovative questions, data, and approaches, as well as innovative reexaminations of existing theoretical frameworks, making a meaningful contribution to the understanding of Arabic linguistic structure and human language representation/processing throughout all papers. The volume is intended to highlight the potential contribution of Arabic linguistics and to endorse further contributions to the sparse knowledge of language representation and processing in Arabic to further develop our understanding of innate linguistic knowledge. It draws special attention to the potential contribution of studies of diversity in Arabic dialects and between the two language varieties of Arabic, for the broader study of human language.