Maybe his inability to talk makes you feel unsure.
Alliances with various land powers, and an inability to understand the true relations which alone could unite the league, combined to alienate the allies, who could discover no reason for the expenditure of their contributions on protecting Sparta or Corinth against Thebes.
I made no effort to teach her to speak, because I regarded her inability to watch the lips of others as an insurmountable obstacle.
If he was self-conscious about his inability to talk, he gave no indication.
Maybe his inability to talk was more a case of unwillingness to talk.