He has been professor of comparative and Indo-European linguistics at the Free University of Berlin since 1996. After receiving his Ph.D. from the University of Zurich in 1973, he became Ernst Risch's assistant there before going on to postdoctoral research in Erlangen, Paris, and Harvard. Afterward, he spent three years as a lecturer at Zürich and Fribourg. In 1984 he joined the editorial team of the Lexikon des frühgriechischen Epos, becoming verantwortlicher Redaktor in 1987 (responsible for fascicles 12 (1987) - 20 (2004)).
Amongst his notable publications are the Griechische Sprachwissenschaft (2 vols., 1992) and Indogermanische Sprachwissenschaft (2nd edn. 2002; English version, Indo-European Linguistics, 2003).