This is intended game behaviour. You play as a deaf character, Dane, and experience the world as the character does, with very little distinct audio and no subtitles. It’s up to you to make up your own interpretation of the story as it unfolds.
A free patch update allowing players to play the game for a second time with sound enabled is planned approximately one week after release. Players will still have to play the first playthrough without audio before being able to play the second one with sound-enabled.