Loud as a Whisper
To the surprise of the away team, headed by Captain Picard, it soon becomes apparent that Riva is deaf. Although he can understand what the crew is saying by reading their lips, his only way of communicating is through the Chorus, a group of three people who not only possess a distinctive aspect of Riva's personality, but can read the mediator's thoughts telepathically and translate them into words.
Arriving at the war-torn planet, Riva, his Chorus and the away team prepare to meet with the leaders of the centuries-old dispute. But when the combatants face each other to begin the peace talks, a dissident soldier opens fire with his weapon, killing Riva's Chorus. The away team and Riva are quickly beamed back aboard the U.S.S. Enterprise before more harm is done.
Faced with the loss of his Chorus, Riva becomes withdrawn and loses all confidence in himself. Although Data learns several forms of sign language and is able to communicate the deaf man's thoughts, Riva refuses to return to the planet where his friends were so needlessly killed. Luckily, Troi is able to persuade Riva that he can turn his disadvantage into an advantage.
Back on Solais V, Riva dismisses Data as his translator, announcing that he plans to teach the warring leaders sign language so that they can communicate with him and, in turn, with each other.