His research and teaching interests spanned the fields of Linguistics, Classics, Literature, Near Eastern Studies, and Religion.
He also commanded some competency in a wide range of languages, including Ancient Greek, Latin, Sanskrit, Hittite, Old Persian, Classical Armenian, Yiddish, Hebrew, Norse, Old English, Frisian, Old Saxon, Old Irish, Breton, German, French, Italian, Spanish, Portuguese, and Russian.
He worked for Bain Management Consultancy in London, England before pursuing his passion for language, learning and teaching at Princeton University in 1985.
Before coming to Middlebury College in 2003, where he served as a visiting assistant professor of German and linguistics, Southern served as an assistant professor in the Department of Germanic Studies at the University of Texas, Austin (UT); as assistant professor of German and linguistics in the Department of Modern Languages at Carthage College in Kenosha, Wisconsin; and as a teaching fellow in arts and literature at Harvard University.
[citation needed] On 15 March 2006, at age 45, he died at his home in Middlebury, Vermont.