He was also a leader in the field of African linguistics, though his ideas are now mainly considered to be outdated. Based on his work in the ancient Egyptian language, and his field work in the Sudan, Lepsius developed a Standard Alphabet for transliterating African Languages; it was published 1855 and revised in 1863. His 1880 Nubische Grammatik mit einer Einleitung über die Völker und Sprachen Afrika's contains a sketch of African peoples and a classification of African languages, as well as a grammar of the Nubian languages.