Nicholas N. Poppe (Russian: Никола́й/Ни́колас Никола́евич Поппе, Nikoláj/Níkolas Nikolájevič Poppe; 27 July 1897 – 8 August 1991) was an important Russian linguist. He is also known as Nikolaus Poppe, with his first name in its German form. He is often cited as N.N. Poppe in academic publications. Poppe was a leading specialist in the Mongolic languages and the hypothetical (and controversial) Altaic language family to which the Mongolic, Turkic, and Tungusic languages belong. Poppe was open-minded toward the inclusion of Korean in Altaic, but regarded the evidence for the inclusion of Korean as weaker than that for the inclusion of Mongolic, Turkic, and Tungusic. Source: Wikipedia (en)