My main areas of interest can be categorized as follows: historical linguistics, Greek linguistics, Balkan linguistics, and morphological theory, with secondary areas of interest being language and ethnicity, Sanskrit linguistics, and Indo-European linguistics in general.

My central scholarly focus throughout my career has been the study of how languages change through time. I have been guided, moreover, by the belief that the study of language change is crucial to understanding the nature of human language in general, since languages are not static, unchanging entities, but rather are continually in flux. Whatever insights have emerged from my work have come largely through the examination of how one language, Greek, has developed from prehistoric times (c. 2000 BC) up through the present, thus covering a span of some 3500 years. At the same time, working on the premise that to be a good historical linguist, one must be a good linguist, I have tried to contribute to the analysis of the Greek language at various periods in its development, but especially the Modern Greek stage.

In doing this, inasmuch as a detailed understanding of the workings of a single language is a good basis from which to understand human language more generally, I have worked toward the development of a general theory of human linguistic competence that focuses on how speakers strike a balance between generalizing over limited sets of language data and learning highly particularized information about individual lexical items, grammatical suffixes and prefixes, and constructions. Finally, working on the historical development of Greek, a language which has been in close contact with numerous other languages throughout its history, has led me into the study of what happens under conditions of intense contact between speakers of different languages, and specifically the special circumstances that have led to convergences among the languages of the Balkans in the past millennium.