Here are 5 steps. I don't know if all these work, but I had a friend like that, but they hang out more with others rather than me. We still chat together, although.
A1: Understand why they don't like you talking to them.
B2: Listen to your friends, and bring up any memories that may connect to why they don't want you to speak with them.
C3: Cope with and understand life changes.
D4: Keep calm and leave them alone. Sometimes they will understand how you feel and eventually speak to them.
E5: Do what you like to do to keep yourself happy, just in case you feel down or sad.
If all else fails, I don't know what to tell you.