Sommerfelt, Alf (1890–1965), Celtic scholar and linguist, was born 1890 in Trondheim, Norway, son of secondary school principal Axelsson Sommerfelt. His mother's name and details of his early education are unknown. He matriculated at the University of Oslo in 1911 where he studied old Norse, the classical languages, Sanskrit and comparative Indo-European linguistics under a number of teachers including Carl Marstrander (qv). He first visited Ireland in 1915 after completing four years at university but unlike many of his contemporaries he chose Donegal to learn Irish rather than Kerry, due to the influence of E. C. Quiggin's A dialect of Donegal (1906). He spent nine months in the glen of Torr with the Mac Maonghail family and according to his own account, would have died from influenza in 1916 if it had not been for the care he received from them. He published an account of the phonology of the area, The dialect of Torr, Co. Donegal (1922), having completed the manuscript in 1918. He later substantially revised this work in Lochlann, iii (1965). As a result of his efforts, the dialect of Torr is one of the most comprehensively described of the Celtic countries.
After leaving Ireland, he transferred to the Sorbonne, Paris, where he continued his studies in general and comparative linguistics, general phonetics, dialect geography, and Celtic linguistics. Amongst his teachers there were Loth, Meillet, Rousselot, Gilliéron and Vendryes. During his time in France, between 1917 and 1919, he spent long periods studying Breton in Finistère, Brittany. He graduated with the degree of docteur ès lettres in 1921 and subsequently returned to Oslo where he held a research fellowship in comparative linguistics in Oslo. The following year, 1922, he became editor of the unilateral dictionary of Norwegian Riksmål (Dano-Norwegian), the Norsk Riksmålsordbok, which appeared in fasciculi between 1937 and 1957. Apart from a period of exile in England during the German occupation of Norway from 1940 to 1945, Sommerfelt was actively involved in the dictionary and compiled and wrote a substantial part of the work, approximately 3,750 two-column octavo pages. Between 1922 and 1925 he visited Wales three times to conduct fieldwork. He was appointed associate professor of comparative and general linguistics in Oslo in 1926, the first time the term ‘general linguistics’ had been used in the title of a Norwegian university post. He was appointed to the newly created chair of comparative and general linguistics also in Oslo in 1931 and held the post until his retirement in 1962. As a result of his interest in comparative linguistics, he visited the Caucasus in 1931 where he carried out a field study. He published his findings in a series of articles entitled Études comparatives sur le caucasique de nord-est, the first of which appeared in 1934.
His other publications include Le Breton parlé à Saint-Pol-de-Léon (Phonetique et morphologie) (1920) of which only a limited number of copies were printed; ‘Le système verbal en Cath Catharda’ published in the Revue Celtique, 1915–23; D? en italo-celtique (1921), his first contribution to European linguistics; Studies in Cyfeiliog Welsh (1925); South Armagh Irish (1929) and Sproget som samfundsorgan (1935). La langue et la société (1938) consisted of an analysis of the linguistic and social structures of the Australian Aranta tribe and was considered by Sommerfelt himself to be his magnum opus. He was particularly interested in socio-linguistics, reflected in Språket og menneskene (1948). He founded the journal Lochlann, which first appeared in 1958 and edited three volumes in the series. At the instigation of Roman Jakobson, a large selection of Sommerfelt's articles was published in Diachronic and synchronic aspects of language (1962).
Apart from his academic duties, he was also involved in administrative work as dean of the faculty of letters and pro-rector of the University of Oslo. During the second world war he held a position in the Ministry of Education in the exiled Norwegian government in London. He was one of the founders of UNESCO, serving on its committee between 1946 and 1952 and was a member of CIPL (Permanent International Committee of Linguistics) of which he was secretary general for a number of years and later president. He was also a member of CIPSH (International Council of Philosophy and Humanistic Sciences). He received a number of awards and honorary degrees including an honorary degree from the NUI in 1951.
In 1941 he addressed a memorandum to the DIAS and Taoiseach Éamon de Valera (qv) on the necessity of an Irish linguistic survey, in which he supported preparing an Irish linguistic atlas.
His wife Aimée was the author of a number of novels for teenagers. Sommerfelt died as a result of a road accident in Oslo 12 October 1965.