Sonya was just steadying herself to her feet, just until she spotted the assailant preparing to beat Sonic to the ground. "Let him go!", she snarled, once she got to her feet. She was just about ready to pounce on the odd red figure, but she managed to stop herself once she heard her little brother try to talk some sense into his attacker. So he was a mobian too? A pretty violent one, that is. Did he escape from a lab too? 

For Sonic's sake, the elder went right with the conversation; really to hold back from retaliating against him for advancing on them in the first place. "We're mobian too; hedgehogs, that is", she has never seen a specimen like him before. "My name is Sonya; this is Sonic. We don't mean to intrude. We just need a place to stay", she probably figured that this individual was trying to protect its territory. It would probably be best to break the ice if they were to share it.