In the late 20th century, interest in Whorf's ideas experienced a resurgence, and a new generation of scholars began reading Whorf's works, arguing that previous critiques had only engaged superficially with Whorf's actual ideas, or had attributed to him ideas he had never expressed. The field of linguistic relativity studies remains an active focus of research in psycholinguistics and linguistic anthropology, and continues to generate debate and controversy between proponents of relativism and proponents of universalism. By comparison, Whorf's other work in linguistics, the development of such concepts as the allophone and the cryptotype, and the formulation of "Whorf's law" in Uto-Aztecan historical linguistics, have met with broad acceptance.