Too often people define self-advocacy in narrow terms. They define it in terms of formal groups like People First or Autism Network International. They define it in terms of the ability to use standard language in a specific set of ways. They define it in terms of a specific method of going through the legal system, or other usual channels, to get specific kinds of things done. These are all valid kinds of self-advocacy, but they set people up to believe that only certain kinds of people could ever become self-advocates.
When one inmate in an institution fights back against the staff in defense of another inmate who is being brutalized, this is self-advocacy. I have only seen this happen once. She was brave and heroic in the genuine senses of the words, and she paid the price for trying to protect me.