The son of Aaron Selig Dionach, a Russian Zionist who had previously been imprisoned for attending the memorial service for Theodor Herzl, Nakdimon had his early education at Haberdashers' Aske's Boys' School.
[1] He began studying Hebrew, Greek and Latin at King's College, London in 1923.
[2] Doniach joined the RAF in the Second World War and was soon after headhunted to serve at Bletchley Park.
After 11 years, in which he reached the rank of Squadron Leader, he moved to the Foreign Office department at GCHQ Cheltenham, where he became Director of the Technical Language Section.
[2] During the Cold War he was involved in teaching the Russian language to Foreign Office employees and helped create dictionaries for members of the British intelligence services.