While in phonology Middle Indo-Aryan (MIA) dialects preserved the phonological system of Old Indo-Aryan (OIA) virtually intact, their morphosyntax underwent far-reaching changes, which altered fundamentally the synthetic morphology of earlier Prākrits in the direction of the analytic typology of New Indo-Aryan (NIA). Speaking holistically, the “accusative alignment” of OIA (Vedic Sanskrit) was restructured as an “ergative alignment” in Western IA languages, and it is precisely during the Late MIA period (ca. 5th–12th centuries
(a) We shall start with the restructuring of the nominal case system in terms of the reduction of the number of cases from seven to four. This phonologically motivated process resulted ultimately in the rise of the binary distinction of the “absolutive” versus “oblique” case at the end of the MIA period). (b) The crucial role of animacy in the restructuring of the pronominal system and the rise of the “double-oblique” system in Ardha-Māgadhī and Western Apabhramśa will be explicated. (c) In the verbal system we witness complete remodeling of the aspectual system as a consequence of the loss of earlier synthetic forms expressing the perfective (Aorist) and “retrospective” (Perfect) aspect. Early Prākrits (Pāli) preserved their sigmatic Aorists (and the sigmatic Future) until late MIA centuries, while on the Iranian side the loss of the “sigmatic” aorist was accelerated in Middle Persian by the “weakening” of s > h > Ø. (d) The development and the establishment of “ergative alignment” at the end of the MIA period will be presented as a consequence of the above typological changes: the rise of the “absolutive” vs. “oblique” case system; the loss of the finite morphology of the perfective and retrospective aspect; and the recreation of the aspectual contrast of perfectivity by means of quasinominal (participial) forms. (e) Concurrently with the development toward the analyticity in grammatical aspect, we witness the evolution of lexical aspect (Aktionsart) ushering in the florescence of “serial” verbs in New Indo-Aryan.
On the whole, a contingency view of alignment considers the increase in ergativity as a by-product of the restoration of the OIA aspectual triad: Imperfective–Perfective–Perfect (in morphological terms Present–Aorist–Perfect). The NIA Perfective and Perfect are aligned ergatively, while their finite OIA ancestors (Aorist and Perfect) were aligned accusatively. Detailed linguistic analysis of Middle Indo-Aryan texts offers us a unique opportunity for a deeper comprehension of the formative period of the NIA state of affairs.