Aphasia typically results from brain damage, such as a stroke (caused by a blocked or ruptured blood vessel in the brain). Such damage leads to the death of cells in the brain regions that control language, impairing abilities in speaking, expressing oneself, and understanding spoken words.

Besides stroke, other conditions that can lead to aphasia include: Alzheimer's disease, dementia, brain tumors, brain aneurysms, epilepsy, brain surgeries, cerebral hypoxia (insufficient oxygen supply to the brain), toxins, and poisonings. Migraine can also cause temporary aphasia in some cases.

The main causes of aphasia are:
* Stroke
* Cerebral hemorrhage
* Alzheimer's disease
* Dementia
* Brain tumors
* Brain aneurysms
* Brain surgeries
* Cerebral hypoxia
* Epilepsy
* Migraine (temporary)
* Toxins and poisonings
* Transient ischemic attacks (TIA)