I don't really understand the reason of the first posting in this thread. Does the author believe that coded material is the ONLY way we humans have to express thoughts, attitudes, impressions, and so on? In that sense, and only in that restricted sense, does the question have some meaning for me, although I immediately react to the implications such a "traditional" view develops.
I think humans have the power to express almost anything they want using all sorts of possible means at their disposal, one of them being, of course, their coded linguistic tool. These linguistic tools are only helping tools, and it is immaterial whether they are more or less morphologically complex or whatever. They all do the same work.
Speaking only about terminology, to believe that because in English you have coded terms for afternoon, evening and night, whereas we only have two terms, tarde and noche, we, therefore, may not express the "evening" situation is not really true. We use other elements to point to exactly the same time-span when need be. Not everything has to be coded to be expressed.
On the other hand, it is true that sometimes, the exact interpretation of a given expression depends on a series of factors, some of them very weakly manifest, but important all the same.
Take a caption in one of the French comic-stripes of ASTÈRIX. At one point, in the French version, when Astérix sees the Romans coming, he calls out (in French):
"XXII, les romains!"
This sentence is translated exactly in the Spanish version as:
¡XXII, los romanos!
But it has no meaning whatsoever in that new version, although the same coded material is presented. In France (but not in other francophone countries), when you see the road-police which travels in motorbikes in couples, the argot expression to watch out is (I have no idea why): Vingt deux, les flics!.
The Astèrix exclamation (with its Roman numbering) drives the French immediately to that representation, producing all sorts of connoted meanings which are totally lost in the Spanish version. Is this, then, a proof that translations are impossible? Well, if you are super-touchy, you might arrive to that conclusion. But you can approach the message by using an altogether different expression (¡Coño! ¡La pasma romana!, could be one), although you are never going to produce the same communicative effect in the readers.
That's what interpretations (and translations are interpretations) do all the time. They change the meaning of the messages, although these changes are not terribly important and the gist of the messages is preserved.
What I wanted to stress with the example is that no matter how similar the coded messages seem to be, the meaning they convey needs a lot more than just decoding them. Ergo, the coded material is not fundamental when we try to find out the expressive faculty of human communication.
