Astrophel

Astrophel is very seclusive, but with good reason. It was both physically and mentally exhausting to try and converse with his clanmates all day, and usually they didn't have an interesting conversation topic anyways. Anytime someone mentioned astrology, he tried to pipe up with a neat fact, but his voice is never heard, drowned out among a sea of dragons who are louder and more confident in their ability to speak.
He got tired of trying, of being talked over. Instead, he turned to the stars, mapping out constellations and flying underneath them.
It's soothing, how calm and quiet it is above ground at night. Most days, the skies were dragon-free, with the occasional traveler or courier. He doesn't feel the need to speak up here, to try and 'fit in'. Among the stars, he was free.
He uses his already-quiet voice less and less as he slowly accepts himself. It was perfectly fine to not want to talk, he didn't have to, he didn't want to. He surrounds himself with the stars, with books and maps and research.
One day, he tried to organize his thoughts by talking to himself as he flew.
No words came out.
His mouth moved, but made no sound. He tried stretching his jaw, tried breathing exercises and took a break. Nothing worked, and he floated confused in the air.
His ability to speak was gone.
It was hard trying to explain it to his clanmates without his voice, but he learns of an ability he didn't know he had: He could read minds.
He tries communicating that way by projecting his thoughts, and it works! His clanmates are shocked the first few times they hear his voice in their head, but they soon adjust. He also takes to writing what he wanted to say, in case he couldn't quite organize it in his head.
Astrophel is mute, and he accepts that. Everyone does after a while. They start acknowledging him in conversations, because his thoughts are louder, louder than the voice he once had. They acknowledge him, and he's able to speak his mind and give his opinions without being drowned out anymore.
Finally, finally he can be heard without the need to speak.