Bradley had humble beginnings as a farmer’s son in Nottinghamshire, but by adolescence he was already steeped in several languages of Classical learning, and he is supposed to have learned Russian in only 14 days. Simon Winchester records that some of Bradley's childhood notebooks, discovered by a friend, contained
...lists of words peculiar to the Pentateuch or Isaiah, Hebrew singletons, the form of the verb to be in Algerine, Arabic, bardic and cuneiform lettering, Arabisms and Chaldaisms in the New Testament, with vocabularies that imply he was reading Homer, Virgil, Sallust and the Hebrew Old Testament at the same time. In another group the notes pass from the life of Antar ben Toofail by 'Admar' (apparently of the age of Haroun Arrashid) to the rules of Latin verse, Hakluyt and Hebrew accents, whereupon follow notes on Sir William Hamilton and Dugald Stewart and a translation of parts of Aeschylus' Prometheus...
For a long time, he was employed as a simple corresponding clerk for a cutlery firm in Sheffield. The first public outlet for his erudition was as a columnist in the Academy, a weekly literary magazine run by J. S. Cotton in London.
Bradley came to James Murray's attention in February 1884 when he reviewed the first fascicle of the OED, A–Ant, in the Academy. Bradley's review praised the clear format and simple design of the dictionary and its economy in using quotations, but it also challenged Murray's etymology, and this caused quite a stir. At the time, Bradley was an unknown freelance writer with no official academic credentials, yet his essay, showing a close knowledge of several languages, contained criticism that none of Murray's colleagues had been able to provide. Anemone could not correctly be rendered as "daughter of the wind," for example, because the Greek suffix was not "exclusively patronymic," and alpaca was not Arabic in origin, as Murray had written, but more likely Spanish.
Bradley's triumph was that both his praise and his criticism were fair and well-tempered; he was admiring without being sycophantic and corrective without being hostile. Recognizing that he had found a worthy peer who could prove invaluable in creating the Dictionary, Murray hired Bradley, first as an assistant editor, then as joint senior editor.