: Then, please, do not simply revert but add other sources to it. As for the sources: in controversial topics, the EI and EIr are considered authoritative (i.e. when there is no equally scholastic source available). In addition, Carter Vaughn Findley is a notable specialist of Turkic studies and the author of the book "Turks in World History", published by the Oxford University Press in 2005. And his source clearly says:  
 :*"... Many elements of Non-Turkic origin also became part of Türk statecraft [...] for example, as in the case of khatun [...] and beg [...] both terms being of Sogdian origin and ever since in common use in Turkish. ..." (p. 45, link to Google Books).