The two crossword solutions for the term 'inability to speak' are MUTISM (6 letters) and Alalia (6 letters). MUTISM is a condition in which a person is unable to speak, either due to psychological or physical causes. It is usually caused by psychological trauma or a neurological disorder. Alalia is a form of speech impairment that affects the ability to produce or comprehend language. It can be caused by a variety of conditions, including hearing loss, brain injury, or developmental disorders.