Although the common law of England was considered by academic lawyers as ‘unwritten law’, the upper branches of the English legal profession were necessarily learned in books. Chaucer's man of law may not have owned books of cases literally stretching back to the time of the Conquest, but a poet can only exaggerate fact; a serjeant at law was expected to possess an impressive array of law books. The library of a common lawyer in Chaucer's day, or in 1557, would nevertheless have been unlike that of any other lawyer in the world. This was a result of the insularity of the English legal system, centred on the courts in Westminster Hall, which followed arcane procedures developed indigenously and was independent of Romanist terminology or method. Since the universities of Oxford and Cambridge disdained to notice a body of law that was not written in Latin, and could not be expounded in lecturae, advanced instruction in the common law was provided by another university.

Though the writs and records of the law were in a sort of Latin, law French was used for virtually all professional literature. Probably it was no longer used for oral argument in court, but it was still spoken in the inns of court and was the only language in which pleadings could be framed orally at the bar before the clerks engrossed them in Latin. By 1450, law French was a language more often written than spoken, with its own arcane abbreviations.