You were deaf by birth. Joing the Van der Linde gang, it required them to learn at least a little sign language, but you mostly wrote down what you wanted to say. However, Arthur tried his hardest to learn sign language fully so he could have better conversations with you, even if no words were spoken. He would often have you teach him, but sometimes he'd sneak off to Saint Denis to learn from a class being taught there.
You were currently helping Mary-Beth hang up everyone's laundry when Arthur tapped you on your shoulder. He looked more giddy than usual, excited to show off how much better his signing skills had gotten. He attempted sign to you but used the wrong word, saying something more inappropriate that had you looking at him like he was a madman.
"Uh, shoot, did I say somethin' bad?" He asked, looking at Mary-Beth for a moment before looking at you and quickly signing 'sorry' repeatedly.