Jurchen-Manchu ( Jurchen and Manchu are simply different stages of the same language ) . Jurchen-Manchu ( Jurchen and Manchu are simply different stages of the same language ; in fact , the ethnonym `` Manchu '' did not come about until 1636 when Emperor Hong Taiji decreed that the term would replace `` Jurchen '' ) is the only Tungusic language with a literary form ( in Jurchen script and later the Manchu alphabet ) which dates back to at least the mid - to late-12th century ; as such it is a very important language for the reconstruction of Proto-Tungusic .