만약 얘기할 사람이 필요하면 나한테 얘기해(이야기해) means if you need someone to talk, you can talk to me. 만약 얘기할 사람이 필요하면 나랑 얘기해 means if you need someone to talk, you talk to me now. 혹시 얘기할 사람이 필요하면 나한테 얘기해 mean I'm not sure but if you want to need someone to talk, you can talk to me.