On the very idea of an conceptual scheme
Conceptual schemes are ways of organizing experience, existing as systems that organize and make the data on sensation intelligible. In other words, they are particular ways in which individuals, cultures or historic and geographic groups look at the world and the particular scenes that pass by. We may or may not be able to go from one conceptual scheme to another. Whorf posited that there may not be a way to translate Hopi into English. Yet even so, it seems possible to translate one conceptual scheme into another.
Even people who belive there is one true reality, posit there being different conceptual schemes which are false. We could argue that language acts to distort the true depiction of reality, which implies it is only through wordlessness in which we understand the true reality of the world.
There are two kinds of failures in translationabiliy: complete and partial. With a complete failure, we do not grasp any of what is being said, a partial failure refers to getting some of what is being said, but not enough to completely underedstand what is being said.
While Saturnian could be translated into english, and Saturnian could be translated into Plutonian, this does not mean that Plutonian can be translated into English. But while we cannot directly translate English to plutonian, we may be able to indirectly translate what is being said. Yet another possibility may arise however: that there might be enough differences in the translation process that it ends up being untranslatable. Kind of like a game of Chinese whispers, where what was once said and being x, has been changed into something completely different such as y. We would still have to wonder in the process of translating plutonian to english, if the saturnian was acurate in what he was translating.
Philosophers like Feyerband, argue we may compare conceptual schemes by existing outside language. He hopes that human experiance is a pure and essential thing in itself by positing this. Certain philosophers, by focusing on how sense experiance provides evidence for the truth/falisty of a sentence, thereby get around conceptual relativism.
We could perhaps argue that nothing makes sentences and theories true. The likes of experiance, the world, etc., cannot make a sentence true. A sentance might corrospond with the an experiance, a fact, etc. but this does not mean the sentance by virtue to its corrospondence truth.