He also learnt Chinese, because he discovered that although the Hsiung-nu and the Mongols had no historical records of their own, detailed accounts survive in Chinese history down the centuries. So an ability to read Chinese sources was essential for further study of the subject.
因為他發覺，匈奴、蒙古人自己沒有留下史料，例是在中國各代歷史中可以找到關於他們的詳細記載，如果不研究中國材料，就不能繼續做下去。