Preach Cristi. I'd go further. Forgive me if this a little lacking in evidence, maybe. A distinction that Cristi makes is words as referent to real physical objects, or visible (since the sky may not necessarily be physical, but at least our experience of it is sensual). There are of course words that refer to things which are not physical, tactile, sensual, holdable. Love, hate, malice, envy, value... True and false are also in this category. One cannot hold truth.
And here's where I think I'd go farther. We only apply a value of truth (or falseness) to a statement. When we say that "the sky is blue" is "true", we are not saying that "the sky is truly blue", but that "the sky is blue" is a true statement. There is--to my mind--no way to evaluate the truth of anything outside of language. Language is the tool by which we identify the senses.
Think of math. We are presented with numbers, which are symbolic equivalents to the amounts they represent. A number on it's own is not true or false. What can be said of the truth or falseness of two. Nothing. We can only begin to evaluate "truth" in relation to numbers by placing them in equations. 2+2=4 and the like. Only when placed in relation to one another can such an analysis begin. 2+2 does not equal 5.
A sentence is the same. The words themselves, and the things they represent are themselves beyond truth. What after all is the difference in truth between a physical chair and the word chair? Both are objects, sensually experienced. They carry no truth value of their own. They are what they are. Chair=Chair. Only when we linguistically place them in equations of action, definition and the like can we even begin to comprehend "truth" in relation to the objects. And even then it is not about the objects themselves, but about the statement.