Arabic morphology: from morphome to morpheme

Abstract Morphological exponence in Arabic verbal morphology deploys at least three concurrent realizational means: affixation, prosodic templatic variation, and stem-vowel alternation or ablaut). In this paper, we focus on stem-vowel alternation as a morphological exponent in Arabic verbal paradigms, mainly in the second stem-vowel (V2). Traditional accounts have associated V2 alternation mainly with aspect and voice . We show that such accounts fail to capture the full picture. Adopting a comparative dialectal perspective, we demonstrate that V2 ablaut displays two distinct grammatical profiles in the Arabic dialect continuum. In Standard Arabic and many Eastern dialects, the distribution of V2 alternation is best analyzed as morphomic , since it does not consistently map onto a single morphosyntactic or morphosemantic class across derivationally related verbal measures. In Western dialects, by contrast, this same alternation, at least across the set of V-final verbs (defective), can be analyzed as morphemic, encoding a valency contrast between transitive and intransitive stems. Our analysis further reveals a systematic East–West divide in Arabic verbal morphology. More generally, we argue that Arabic provides a striking case of distributed exponence, in which V2 alternation overlaps functionally both with templatic structure and affixation in the realization of aspect, voice , and valency . Additionally, by tracing the diachronic shift in Arabic verbal morphology from morphomic patterning to morphemic interpretation, we aim to shed light on how morphological systems may evolve toward grammatical transparency.