You're really just falling apart, i mean if my 'red' was the color red, and your red was my blue, and steve's red was my green, you just wouldn't logically be able to talk about things. if things were completely subjective you'd have a lot of cases where some people would be able to see massive contrast and others would see no contrast, despite all the physical structures of the eye being functional.
how would it be if all things were subjective, you just oculdn't have language, you wouldn't be able to share a common experiance, but we do.
Post above is pretty good at explaining things
again, read Davidson, Pierce, Wittgenstein, their theorys of semantics, language and meaning, all deal with this sort of problem