deduce - verb

In no department are American universities weaker than in the department of English. The æsthetic opinion that they disseminate is flabby and childish, and their philological work in the national language is extraordinarily lacking in enterprise. No attempt to deduce the principles of vulgar American grammar from the everyday speech of the people has ever been made by an American philologist.

—H. L. Mencken The American Language (1921)