Ian Hollenbaugh's research interests include Indo-European linguistics, Homeric Greek, Old Latin, Vedic Sanskrit, and Germanic languages.
He focuses particularly on the tense and aspect systems of Indo-European languages from both diachronic and synchronic perspectives. His current projects include annotated digital corpora of the Rigveda and the Iliad, tagged for morphological and semantic information. He is also working on a monograph on the Indo-European verb. Most recently, he has published on the development of the Greek imperfect in the Journal of Greek Linguistics (2021) and on the Sanskrit prohibitive construction in the Journal of the American Oriental Society (2020).