The Hero of Oakvale: Headcanons and Theories
To preface, a lot of this post is based on my ideas and personal thoughts. However, I love friendly discussion, so feel free to share ideas!
Now, to my recollection, the Hero of Oakvale (HoO for ease) is one of the view protagonists we see have his trauma brought up in a realistic way, specifically in the flashback when you return to Oakvale.
He sees the woman who owned Rosie, hears her speaking... And suddenly she's the little girl she was the day the bandits attacked. The village is burning, he's hearing screams, and he's panicking.
His flashback, while quick, is intense and you get a sense that the attack effects him far more in adulthood than is fully explored.
Though, personally, I think story wise, the HoO is used to suppressing his grief. He had to. Maze, Weaver... Every adult he met that night and after failed him. He wasn't allowed to grieve properly or in his own time. So, he used his training as an outlet, and a way to bury his pain and his suffering. We don't explore his grief more because by then, even he struggles to cope with it.
He lost everything at once, his family, his neighbors, his friends, his home... And not one person let him grieve in full.
While, mechanically speaking, having the HoO speak might have caused issues, I think in universe, he was just a quiet kid. A kid who spoke really only at home. But as an adult? I think he's 98.75% mute by choice. (The percent based on the occasional word said during emotes.)
I think he got used to feeling alone and unable to speak about his pain that he just... Stopped talking. He stopped trying to communicate verbally. I headcanon that he uses gestures and sign language where he can, and that the emotes and actions are him trying to communicate without having to talk.
And I imagine him falling for someone, trying to woo them, and succeeding despite rarely saying a word. I imagine his spouse being sad he doesn't talk, but them being even sadder to see the far away, dead eyed look he gets seeing the fireplace going.
When they move to Oakvale (I know you can't move spouses in Fable 1 but I headcanon he would be married once and live in his old home in Oakvale), his spouse finds him sitting on the step, dozing like he had as a child. They see him by the barns, watching chickens...
And Oakvale being the one place they hear him speak most. He tells them about his childhood in a soft, unused voice. He avoids discussing Theresa, Brom, and Scarlett... Avoids even their names.
As he ages, and the more bs he has to deal with, the more cynical the HoO becomes.
Hes still kind and helpful, but Whisper's taunts are grating and hurtful. Thunder's attitude is infuriating. Weaver's reminders are annoying at best.
He loves his big sister and would die for her. She is everything to him when he finds her again. But as she gives him graver and graver news and prophecies, he finds seeing her anxiety inducing.
Realistically, the HoO is an extremely broken and traumatized person. Someone who never really gets a happy end.
His own teacher betrays him. Someone he thought cared about him, but only wanted to use him. Maze was a paternal figure to him, and Maze tried to kill him. I always thought that after that, the HoO had a hard time trusting people again, even those close to him, to the point of isolating himself to some extent...
Tl;Dr: The Hero of Oakvale is broken, traumatized, and was betrayed and lied to repeatedly. He was never allowed peace or space to grieve. He was never really given much choice, and he's just trying his best to be okay and help others.