There is relatively little, as far as I know, that has been written on the ethics of language use. There is this course on social and political aspects of language, which looks great, and I haven't read most of what it covers, but it suggests to me that there is a field waiting to be ploughed. Maybe.
Anyway, as a step in the direction of the plough, here's a sort of list of concerns:
- George Orwell famously warns about thoughtless and vague language, but he doesn't address careful vagueness or how to speak about such subjects as ethics, religion, and art.
- Harry Frankfurt, also famously, critiques bullshit: language intended to produce a certain effect but not concerned with truth. This is a broad category, though, including the relatively thoughtless (with the speaker perhaps hoping for no more than to be left alone) and the very careful (perhaps with very specific goals and clever ideas about how to achieve them). There is also the question of what to call language that is concerned with truth but that tries carefully to mislead without actually lying.
- Steven Poole writes about "unspeak": language that tries both a) to imply an argument without defending it or making it explicit and b) to silence opposition.
- I criticize what I have been calling "political correctness": language that is like bullshit but that is unconcerned, not necessarily with truth, but with conceptual accuracy. It is like unspeak, but it need not be deliberate. (I think I should perhaps call it something else because the term 'political correctness' is so loaded.)
- Another linguistic vice is straightforward lying, although the ethics of lying are rather complicated
- Spoilsports (the relevant reference here is Gadamer, Truth and Method 1989, p. 102): not taking the (language-)game seriously
- Triflers (see Suits, The Grasshopper 2005, p. 60): respecting the rules of the game, but not its goals
- Cheats (Suits again): recognizing goals but not rules
- Sophists (as Egan sees it, p. 12) are like spoilsports but also deny the very possibility of achieving the goal of the game, e.g. Thrasymachus denying the reality of justice
So, can we put all this together to come up with an initial sketch of the landscape? I will probably have to read Suits one of these days, but in the meantime I'm struggling to imagine exactly what cheating in a language-game would be. Lying, perhaps. Trifling, as the name suggests, sounds a lot like not taking the game seriously, which is what defines a spoilsport. And sophists just seem to be a kind of spoilsports.
Deliberate vagueness, carefully constructed (Jesuitical?) bull, and unspeak all seem like forms of cheating. While thoughtless vagueness and bull are more like being a spoilsport out of laziness.
The interesting area, really, (at least to me) is bullshit. Which seems to be quite popular these days.