Paraphasia is a feature of aphasia in which one loses the ability of speaking correctly, substitutes one word for another, and changes words and sentences in an inappropriate way. It often develops after a stroke or brain injury. The patient's speech is fluent but is error-prone, e.g. 'treen' instead of 'train'. Paraphasia can be further sub-divided into 3 categories: Literal/phonological paraphasia, neologistic paraphasias and verbal paraphasias. In literal/phonological paraphasia, more than half of the spoken word is said correctly. An example could be saying pun instead of spun...