In 1970, he was appointed to a Lectureship in Celtic Languages and Literatures at the University of Uppsala, Sweden.
He then moved to a Statutory Lecturer in Modern Irish at University College, Galway in 1976.
In 1980, was appointed Professor of Irish at Ulster University from which he retired in 2014.
[2] These are detailed in the Bibliography of Irish Linguistics and Literature at the Dublin Institute for Advanced Studies.
[4] A Festschrift in his honour was presented to him on his 75th birthday and launched at the 17th International Symposium of Societas Celtologica Nordica held in Uppsala on 7–10 May 2020.