This paper investigates NS perceptions of the coherence and comprehensibility of NNS writing and talk which lacks or misuses grammatical cohesive devices. NS readers of NNS texts with missing cohesive devices assumed coherence and actually imposed coherence on the text by adding grammatical cohesive devices which were missing in the original making implicit semantic relationships explicit. Knowledge of narrative structure and of the world assisted the readers to recover these implicit semantic relationships. NSs also ass tuned coherence and worked to find relationships in the text even where there was potential miscommunication caused by using the wrong cohesive device or by failure to establish a referent. Communication was not usually impaired when the underlying semantic relationship was clear from the discourse context orfrom background knowledge, although NSs had to work hard to understand some texts. Miscomprehension resulted when underlying semantic relationships were not retrievable from other sources.