 He was a specialist in the Greenlandic language (Kalaallisut); his 1974 thesis was the most comprehensive phonological study of that language to date.He published extensively on topics in Danish, Faroese and Greenlandic, particularly phonetics and phonology.From 1978 he was a professor of linguistics at the University of Copenhagen; from 1981 he was chair in phonetics; on his retirement in 1998 he became professor emeritus there.