1. The inability to utter or to understand short phrases (groups of words) that are spoken while still being able to understand or to speak single words: "In conversation with people experiencing aphrasia, the listener may find it difficult to follow the conversation as the speaker may only be able to utter or understand single words, not phrases or sentences."
2. The inability to speak for any cause or reason: "A person who is afflicted with aphasia refuses to speak or has lost the ability to talk."