How often is it that we scroll about the pages of some fantasy or science fiction work, and come across a plethora of words we haven't the slightest clue about. Indeed the realm of science fiction and fantasy seem to be a sort of festering swamp of made up vocabulary conjured on a whim to suit the needs of their creator. Le Guin's "Left Hand of Darkness" is a lighthouse to this trend; glaring with it's brilliant beam of alien dialect.
Yet this is hardly something unique to this day and age; in fact it has a bit of a tradition to fall back upon. Lewis Carroll's "Alice in Wonderland" and "Through the Looking Glass" (which I name together because they are so often lumped as such in popular culture with characters and plots from one being tossed in with the other) did well to establish this tradition of fictional diction.
Take, for instance, the poem included in the story, the Jabberwocky. In of itself a made up word for a made up creature, the first stanza of the poem is almost entirely composed of words that had not existed prior. "Twas brillig and the slithy toves did gyre and gimble in the wabe. All mimsy were the borogoves and the mome raths outgrabe."
Three words come to mind immediately; what the hell!?
Carroll's intend with these words was both to allow for a rhyme scheme that would have troubled him otherwise as well as in a sense parody literature and english society of his time, which most often was so rigid and unyielding in what was considered proper. Part of his point was that language is an intangible and changing thing, and the inflexibilities of convention found in writing then did nothing but parody itself.
In many ways, is this not a part of what we attempt to do with science fiction and fantasy; hold a lamp on the flaws of our current existence through the medium of other alien and fantastic worlds? Le Guin's story and the world it paints for us are meant to offer us an outside lens looking in on a foil to our own messed up existence. Strange and exotic dialects only serve to strengthen the overall illusion by which this is done.