I agree that truth can be relative but it begs the question, are there objective truths in this world? Off the top of my head, I can think of blue is a truth that doesn't need belief in it to be true. Its 'blueness' is evident by our senses, so would that be an objective truth? But again, Fresco might bring up the point that it is an agreed contract between humans to say that this is blue cos some other people call it azzuro or blau or whatever. But in my mind there is no denying the colour, its just how we communicate it that leads to misunderstandings. I think the same could be said about truth.
You are saying that something is "true" blue no matter what the word for "blue" is in one's vocabulary. But have you considered variations in one's organs of visual perception, i.e. the optic nerves? How do you know that you and I are actually seeing the same thing when we both describe it as "blue"? The visual sensation I experience might be quite diffrent from yours. Also, no blue ever stays
blue. It fades into a different shade, it changes colors. If truth is supposed to be somehow eternal, how does your analogy recognize these changes as "true?