I'm an NLP scientist trying to implement a software that take english as input and parse it into a queryable data structure that has zero semantic loss. I'm aware more than anybody on this thread, of the challenges of coreference resolution, word sense disambiguation, semantic parsing, etc... I didn't say that usual language is free of ambiguity. I just said humans are perfectly able to output clear, unambiguous English in a systematic manner. I just needs a little more mental energy.