National language
The Liao dynasty referred to the Khitan language with the term Guoyu 國語 "National language", which was also used by other non-Han Chinese dynasties in China to refer to their languages like Manchu of the Qing, Classical Mongolian during the Yuan dynasty, Jurchen during the Jin, and Xianbei during the Northern Wei. Even today, Mandarin is referred to in Taiwan as Guoyu.