Answer:
Atticus was trying to prove that Mr. Ewell was left-handed because Mayella had been hit on the right side and if Mr. Ewell was left-handed then it would prove he was more than likely the one who inflicted the injuries, not Tom Robinson.
Explanation:
From my understanding, it's the main launguage that people speak based on where there from. I'm not good at explaining but it's like in America, the main launguage people speak is English, while in France most people speak French. Hope this helped!