I find it's more difficult to prove things about natural language than about well-defined specified languages (eg, computer languages). Sometimes a good counter-example is the clearest proof of all. A demonstration of your point can be more practical than a formal proof of it.
English (the natural language) is ambiguous, but it can be very meticulous to formally prove that. Even if you try, a skeptic can just refuse to understand your proof and accuse you of hand-waving tactics and smoke-and-mirror tricks. However, a sentence like "You can't have too much chocolate" very quickly demonstrates the ambiguity. Does that mean:
If you think it has a cut and dry meaning; ask 10 of your friends to paraphrase that sentence and see how it splits.
(p.s. It's post like these that led me to have a "random" category :) )