Aphasia is a communication disorder that affects a person’s ability to process and/or use language. It is a neurological condition caused by damage to the portions of the brain responsible for language, and it does not affect intelligence.
Aphasia can impact ability to understand, speak, read, and/or write words. The sub-types categorize one’s abilities. In most cases, people can improve their abilities with practice.
Anomic Aphasia: Least severe. Understands words, knows what to say, and can speak ok, but often unable to find the correct words (frequent tip-of-your tongue). (My Lisa was at this level, before progressing to Broca’s aphasia.)
Broca’s Aphasia: Understands, knows what to say, but great difficulty speaking. (My Lisa is at this level now.)
Mixed Non-fluent Aphasia: LIMITED understanding, knows what to say, but great difficulty speaking.
Wernicke’s Aphasia: Understands, knows what to say, can speak but speaks the wrong words AND DOES NOT KNOW IT.
Global Aphasia: Most severe. Understands few or no words, can only form a few words, and sentences. Unable to read or write.
Primary Progressive Aphasia: A rare degenerative brain and nervous system disorder that causes speaking and language skills to decline over time. (I do not think my Lisa has this because her understanding has never deteriorated. But, her ability to speak has. Meaning, she has trouble physically speaking.)
The following diagnostic image is from the Aphasia Definitions page from National Aphasia Association website.