Tungusic languages
Among the earlier critics were Gerard Clauson (1956), Gerhard Doerfer (1963), and Alexander Shcherbak. They claimed that the words and features shared by Turkic, Mongolic, and Tungusic languages were for the most part borrowings and that the rest could be attributed to chance resemblances. In 1988, Doerfer again rejected all the genetic claims over these major groups.