The syndrome that is associated with lack of speech is Aphasia.
Aphasia syndrome or aphasia is a disorder which affects how a person communicates.
Aphasia can impact a persons speech and how well the person writes and understands both spoken and written language.
Aphasia often occurs suddenly after a head injury or stroke.
However aphasia can also develop gradually depending on the cause.
Some people that have aphasia fully recover without treatment.
However for most people, some amount of aphasia typically remains.
Speech therapy can often help recover some speech and language functions over time for people with aphasia.
But many people continue to have problems communicating.
Most people with primary progressive aphasia develop other cognitive problems over time, leading to a more general dementia.
You can live alone with aphasia although living alone with aphasia compounds and complicates the extra considerations already required when there is no partner or other caring person in the home.
The buffer against loneliness provided by social connection and meaningful activity may be more difficult to achieve when living with aphasia.