André Vaillant  André Vaillant (November 3, 1890 – April 23, 1977), was a French linguist, philologist and grammarian who specialized in Slavic languages. He was born in Soissons. After studying at École Normale Supérieure in Paris, he taught as professor at the Collège de France, becoming Chair of Slavic Languages and Literatures in 1952. In Russia he studied manuscripts written in Old Church Slavonic. He worked at the Institute of Slavic Studies of Paris. He collaborated in the drafting of the Journal of Slavic Studies which served as the basis for the development of his comparative grammar of Slavic languages . He wrote twenty books including the six-volume Comparative Grammar of Slavic languages ("Grammaire comparée des langues slaves"), the two-volume Handbook of Old Church Slavonic ("Manuel de vieux-slave") and a grammar of Serbo-Croatian together with Antoine Meillet. He translated and published many liturgical texts written in Church Slavonic. He died in Paris.