References in classic literature ?
I see and have seen worse things, and divers things so hideous, that I should neither like to speak of all matters, nor even keep silent about some of them: namely, men who lack everything, except that they have too much of one thing--men who are nothing more than a big eye, or a big mouth, or a big belly, or something else big,--reversed cripples, I call such men.
It needn't be from ear to ear, but it's a fact that a big mouth is often a sign of a certain generosity of mind and feeling.