Tense and aspect in Indo-Aryan languages: Variation and diachrony

This dissertation develops a semantic theory of the imperfective and progressive aspects that explains principal crosslinguistic generalizations made in the grammaticalization and typological literature about the distribution of their morphological exponents (the progressive and imperfective operators). The theory characterizes imperfective and progressive predicates as stative, and derives the distinction between them as resulting from the properties of the larger interval that the denoted intervals are subintervals of. Specifically, imperfective predicates denote intervals that are non-final subintervals of a larger interval within which the predicate is instantiated, while the progressive operator yields the set of intervals that are non-final subintervals of a larger interval at which the predicate is instantiated. This semantics for the two aspectual categories ensures that the denotation of progressive predicates is a subset of the denotation of imperfective predicates, while guaranteeing the stativity of both types of predicates.;The empirical focus of the thesis is on diachronic change and synchronic variation in the imperfective and progressive aspects in a set of Indo-Aryan languages of the Central-Southern subgroup. It is shown how the theory of the imperfective and the progressive developed in this dissertation can explain the progressive-to-imperfective shifts as they are instantiated in Indo-Aryan diachrony and reflected in synchronic variation in the semantic domains of progressive and imperfective morphology. A subset of the New Indo-Aryan languages are non-standard and data for these is based on fieldwork in these linguistic communities. Part of the diachronic data is also based on original textual research. In addition to confirming the theory developed here, the data also supports an empirical claim about the history of the Indo-Aryan tense/aspect system. The claim is that the transition from Old Indo-Aryan to Middle Indo-Aryan is characterized by a loss of morphologically expressed tense distinctions between the present and the past tenses and that the New Indo-Aryan tense/aspect systems must be reconstructed as being fundamentally based on an imperfective-perfective aspectual contrast.