(more ethnic, historic information would be wonderful)
Ancestors of Khitans was the Yuwen[?] clan of the Xianbei. After their regime was conquered by the Murong[?] clan, the remnants scattered in today Inner Mongolia and evolved into Khitan through intermarriage. They had been identified as a distinct ethnic group since paying tribute to the Northern Wei Dynasty in mid 6th century .
Khitan also refers to the now-extinct language once spoken by the Khitan people. There were two writing systems for the Khitan language, known as the large script and the small script; they were functionally independent. The former was derived from Chinese, and the latter was apparently inspired by the Uighur alphabet.
The Khitan language is Altaic, however, and its agglutinizing nature is not particularly suited to purely monosyllabic logographs. The small script had logographs as well as characters which were completely phonemic. The Jurchens (ancestors of the Manchu people) derived their large script in part from Khitan.