It's easy to talk to anyone. No one can stop you from talking to them. If you mean, "What makes it easier to communicate with someone?" , you have to be a good listener. Most people are deficient in listening skills. Information is coming in one ear and going out the other. A good example is, Have you ever had a conversation with someone that goes on and on and you know they told you their name at the beginning of the conversation but after conversing on and on, you somehow forgot their name.
It takes practice, concentration, and determination. You have to have a real concern to communicate with people. You have to care. Many people are so caught up on getting their point across and they end up talking about what they want to talk about but never stop to listen to what the other person is saying.