One of the big questions I had is whether or not evil spirits are able to hear our thoughts. Such an answer would be important for two reasons. First, if they can't hear our thoughts, then praying in my head, while useful and important to speak with my heavenly Father, is not a direct rebuke and confrontation of the evil spirit in my midst. To do battle, then, I should speak audibly. Second, if evil spirits cannot read my mind, then that may influence what I want to say out loud. There may be some fears and weaknesses I don't want to verbalize, which they could use to their advantage were they to know.