https://people.com/health/bruce-willis-has-aphasia-stepping-away-from-acting/?amp=true
"According to Mayo Clinic, aphasia "robs you of the ability to communicate" and "can affect your ability to speak, write and understand language, both verbal and written." The group adds that the condition "typically occurs suddenly after a stroke or a head injury. But it can also come on gradually from a slow-growing brain tumor or a disease that causes progressive, permanent damage (degenerative).""