 He undertook a doctoral programme at the University of London in 1935, and graduating the following year with a Ph.D. from the School of Oriental and African Studies, with a thesis on "The linguistic position of south-eastern Papua", which was published in book form in 1943.His primary interest was the languages of the Pacific and of New Guinea, and he is said to have regarded his research of aboriginal languages to be a matter of weekend work, though he did spend lengthy periods doing fieldwork in both the Kimberleys and Arnhem Land.When A. P. Elkin, then Anglican rector at Morpeth, was appointed to a professorship in anthropology at Sydney, Capell served as his locum tenens in the parish.