Why do I talk a lot at home and little outside?

You are not introverted. Maybe the topic they discussed is not of interest to you. Maybe you don't speak the same language as your friends around you. Or you are a person who likes a calm environment, and only home can give you warmth and give you room to tell. If you meet friends who speak the same language in the future, it will be wonderful and life will be smooth. Don't care if you are an introvert. You are definitely not introverted, just don't talk to strangers.