Prof Kenneth Hurlstone Jackson CBE FRSE FSA DLitt (1 November 1909 – 20 February 1991) was an English linguist and a translator who specialised in the Celtic languages. He demonstrated how the text of the Ulster Cycle of tales, written circa AD 1100, preserves an oral tradition originating some six centuries earlier and reflects Celtic Irish society of the third and fourth century AD. His Celtic Miscellany is a popular standard.
In retirement, Jackson continued his work on place-names and Goidelic languages. However he suffered a stroke in 1984 that restricted his work.
An obituary was published in The Times on 8 March 1991 and in Nomina 15.
Born at Beddington, Surrey, England, he was the son of Alan Stuart Jackson and his wife, Lucy Hurlstone.
His early education was at Hillcrest School, Wallington (1916–19), and then at Whitgift School in Croydon, from 1920-1928. He won an open scholarship to St John's College, Cambridge in 1928. He studied under Hector and Nora Chadwick, becoming fluent in six Celtic languages. At Cambridge he read Classics and then studied the early cultures of Ireland and Britain. He was then awarded a travelling scholarship during which he undertook study and fieldwork in Wales and Ireland. In the 1950s he spent his vacations recording dialects for the Linguistic Survey of Scotland.
Jackson returned to Cambridge in 1934 as a lecturer in Celtic. In 1939 he went to Harvard University and was appointed an associate professor in 1940, being the first chair of the Department of Celtic Language and Literature. He undertook war service with the Uncommon Languages section of British censorship (where he said he learned Japanese in three weeks). Afterwards he went back to Harvard, and became a full professor in 1948. He accepted the chair of Celtic Languages, History and Antiquities at the University of Edinburgh, Scotland (1950–1979).