《新五代史·附录·四夷附录第一》
又对姚坤说： 我会汉话，但对部族人绝口不说，怕他们效法汉人而变得怯弱。 
又谓坤曰： 吾能汉语，然绝口不道于部人，惧其效汉而怯弱也。 
He also told Yao Kun: I can speak the Han language, but I never speak it in front of my tribe in case they would learn from the Han people and become weak.