I basically understand all types of communication, but I have real trouble processing both nonverbal auditory and nonverbals visual at the same time. I find that if I am not part of the group having a conversation, I understand much better/easier than if I'm supposed to contribute to the conversation as well.
I often 'loose' myself in a conversation because I sit trying to figure out whe they meant by that sentance or that reply, and miss bits and pieces, which is quite annoying. Sometimes I spend hours after a conversation trying to figure out if I interpreted things correctly, sometimes even to the point of texting/emailing to chech that I parsed the information correctly.
As far as the written word, that is by far my communication-method of choice, words are often less ambigous on paper because (in my experience) people are more aware of how much information is lost without their tone of voice and gestures. Which, as evident, I am not a champ at.