拙嘴笨舌

Explanation: Clumsy. Mouth and tongue clumsy to describe not good at speech. 　　Usage: Joint type; as the predicate attribute; containing derogatory 　　Source: Qing Going corporal "outlook," I do not have to look everywhere, but the mouth Zhuo blunt tongue, not easily open. " 　　Examples: I am a person of vegetation, ~ of. ★ Yang Shuo, "the pace of the Chinese people standing Hills" Thesaurus:  Awkward in speech, Zhuokoudunsai, Zhuokoudunci