Aphasia is a symptom of some other condition, such as a stroke or a brain tumor. A person with aphasia may: 
Speak in short or incomplete sentences
Speak in sentences that don't make sense
Substitute one word for another or one sound for another
Speak unrecognizable words
Have difficulty finding words
Not understand other people's conversation
Not understand what they read
Write sentences that don't make sense
 Patterns of aphasia People with aphasia may have different strengths and weaknesses in their speech patterns. Sometimes these patterns are labeled as different types of aphasia, including: 
Broca's aphasia 
Wernicke aphasia
Transcortical aphasia
Conduction aphasia
Mixed aphasia
Global aphasia
 These patterns describe how well the person can understand what others say. They also describe how easy it is for the person to speak or to correctly repeat what someone else says. Aphasia may develop slowly over time. When that happens, the aphasia may be labeled with one of these names: 
Logopenic aphasia
Semantic aphasia
Agrammatism
 Many people with aphasia have patterns of speech difficulty that don't match these types. It may help to consider that each person with aphasia has unique symptoms, strengths and weaknesses rather than trying to label a particular type of aphasia.