Tweets? At first that seemed like a little biased prediction set, but on the other hand people who have to make such an effort to communicate will want write few words. However, writing "Tweets" takes almost no effort at all, so it is interesting to consider.
I used tweets because they're informal and mention a lot of "what to do" and "how I feel" topics, which I think is very important for basic communication, especially for individuals with multiple disabilities. A bonus is that I get a lot of pop-cultural lingo (e.g. "Harry Potter", "Hulk SMASH") that makes my suggestions more fitting for informal communication than plain old dictionary lookups. And you are right about the tacitness of tweets - helps in building a list of common phrases like "on my way to" and "by the way."
