What Is Aphasia? Causes, Types, and What to Expect

The word no one teaches you

When Bruce Willis announced his aphasia diagnosis in 2022, the word trended on Google for the first time in years. Millions of people searched "what is aphasia?" — and most were shocked to discover they had never encountered it before, despite it being more common than Parkinson's disease, cerebral palsy, or multiple sclerosis.

Aphasia is an acquired language disorder. It affects a person's ability to speak, understand speech, read, or write — depending on which part of the brain is damaged. It does not affect intelligence. The person with aphasia is still fully themselves. Their thoughts, memories, and personality are intact. The damage is specifically to the neural machinery that converts thoughts into words.

What causes aphasia?

The most common cause by far is ischemic stroke — when a blood clot blocks an artery supplying the brain, starving language-related tissue of oxygen. The left hemisphere of the brain, which controls language in most right-handed people, is where strokes most often cause aphasia. Recognising the early warning signs of a stroke is the single most time-sensitive decision in determining whether aphasia becomes a temporary or lifelong condition — see our guide to the FAST stroke test for the 30-second check anyone can run.

Other causes include:

• ·Hemorrhagic stroke (a burst blood vessel rather than a blockage)
• ·Traumatic brain injury (TBI) — from falls, accidents, or assault
• ·Brain tumours — particularly in or near Broca's or Wernicke's area
• ·Brain infections such as encephalitis
• ·Neurodegenerative conditions — primary progressive aphasia (PPA) is a rare form where language deteriorates gradually without a triggering event

Photo: Unsplash

Types of aphasia

Aphasia is not one condition — it is a family of related disorders, each reflecting which language area was damaged. The most common types are:

What aphasia is not

This is perhaps the most important thing to understand. Aphasia is not a cognitive disorder. People with aphasia are not confused, demented, or intellectually impaired. Their intelligence, memories, and sense of self are intact. The problem is specifically in the translation between thought and language — in both directions.

It is also not the same as dysarthria (a motor speech disorder that affects the physical production of sound, like slurring caused by muscle weakness) or apraxia of speech (difficulty coordinating the mouth movements needed to produce speech, despite knowing what you want to say).

What does recovery look like?

Recovery from aphasia is real and measurable — but it is rarely complete, and it varies enormously. The factors that predict better outcomes include:

• ·Younger age at time of stroke
• ·Smaller lesion size and location (subcortical damage tends to recover better than cortical)
• ·Higher education level prior to stroke (more cognitive reserve)
• ·Early, intensive speech-language therapy
• ·Frequency of meaningful communication practice at home
• ·Strong social and family support

Recovery is most rapid in the first three to six months after a stroke, when the brain is in a heightened state of neuroplasticity. But improvement can continue for years — and with the right intensity of practice, people often make meaningful gains even a decade after their stroke.

The key word is practice. Language recovery requires the brain to rewire — to recruit adjacent neural tissue to take over damaged functions. That rewiring is driven by repetition. An SLP session once a week is not enough on its own. Daily home practice is what makes the difference — and the underlying neuroscience is covered in detail in our piece on the science of aphasia recovery.

For people with primary progressive aphasia specifically, voice banking — capturing a clean recording of your voice while you still can — is an increasingly important early step that an SLP can guide you through.