Among Sethe's many contributions to Egyptology, two are singled out by Gardiner (p. 433): "...the pronunciation of Middle Egyptian... The chief authorities to be consulted are Sethe's great work on the Egyptian verb, and a much later brilliant article entitled Die Vokalisation des Ägyptischen in Zeitschrift der deutschen morgenländischen Gesellschaft"" (1923). Actually, Sethe was the first one to put forth a systematic theory of the Egyptian verb; it was no easy accomplishment, since the flexion of the Egyptian verb was done mainly by changing the vowels, and the Egyptians only wrote consonants.
Among Sethe's students were Polotsky and Gardiner; Sethe's anthology, Aegyptische Lesestuecke, is still doing sterling service to the beginners in the study of the language. Sethe also published a comprehensive collection of Egyptian epigraphy, which he called Urkunden der Aegyptologie.