Do you mean vocally? Or simple incoherence? If it's incoherent verbally it'd be incoherent mentally. Otherwise you could just write it down.

Edit: Thread title seems to be asking a different question. In a free and open society ordinary citizens have only one duty, to follow the law and by extension abide by whatever constitution is present. There are certain obligations, some being more important and pressing than others. Example, having a job or some means to support yourself or rather not passing on the opportunity to grow prosperous, experience whatever national dream or ideal is sought after, and otherwise have a piece of said pie worth talking about. Truth rather "truth" in the lower case is based on circumstance and- contrary to those who base not only their own self-worth but entire identity on would never admit- can change in an instant. Truth, as in Truth, is constant. It is not something that can be known absent of faith by it's very nature and definition. Ergo, the theory that proves everything proves nothing. It is generally religious though observable factors substantiate this ie. times when people believed the Sun revolved around the Earth or flight was impossible. Contrast the two, the former was an absolute falsehood that constituted a subjective reality, whereas the latter was a subjective falsehood that denied an absolute reality.

Perhaps the scenario could be rephrased thus:
Assuming there is an objective truth "out there", which is not accessible to most people, but is accessible to you, does it remain the "objective truth" even if you're the only one that can access it?

In response, mostly lower case. The word 'duty' being taken to mean not solely as in social duty, but also duty to oneself. If the moment escapes me where I have the opportunity to express what appears to be the real truth against false notions, would you say that I have ultimately still won the war but lost the battle? Or maybe you would say that passing up such an opportunity is always unwise, immoral even.

If the moment escapes me where I have the opportunity to express what appears to be the real truth against false notions, would you say that I have ultimately still won the war but lost the battle? — kudos

If the opportunity is not present it's simply not present. There's really nothing to go on about. Separate the art from the artist. You don't make the truth the truth you simply possessed understanding of it. Basically there's no "I" in truth lol.

Or maybe you would say that passing up such an opportunity is always unwise, immoral even. — kudos

Eh, depends. How relevant is this truth and what are the benefits or rather consequences toward those who it would or would not effect? And is it really that big a deal? Do they deserve it? How do you know you're even correct? If you think you know the answer to even one of the aforementioned i'd say it's safe to say it's a truth others will or at least can discover on their own.

Depending, who does the truth benefit? and why is it benefitting?
if the truth will only cause harm and danger it is not worth upholding, but if it benefits people, then yes as it would be a moral ought

Interesting, so you're saying that inclination should play a major role in the decision. Whittling it down further, I suppose the main question could be demonstrated by an example. Person A says, "one plus one is two," and then another says, "you can never have two ones exactly, I say one plus one does not always equal two." Are these two statements both equally worthy of being called the truth? One is being claimed as true primarily of its use of form and the other by primarily by use of content.

Then you could never have two "twos" either. Math is math. Acknowledge his mathematical disinclination and move on. lol

Couldn't the same example hold true for court cases, individuals suffering persecution, authoritarian governments, etc? I put it in mathematical terms to make the distinction being made in clearer terms. Change it to a more practical case such as global warming, nobody benefits from dealing with the truth of this issue, and yet most ordinary citizens still believe they must do something. Why? If someone were to know the truth about a situation like this, I think most people might still favour expressing it.