Over at LL, Geoff Pullum started [a discussion](http://languagelog.ldc.upenn.edu/nll/?p=961) on what the existence of certain lexical items says, if anything, about the culture (let’s say “linguistic community”) in which that lexical item lives. His line (a reasonable one) is, as always, that it says zilch. Well, go over and read the comments. I have my own contribution, but it was getting long, so I’m dumping it here, with no refinements whatsoever.
Perhaps this has been said and I missed it, but here goes: simply finding a word in a dictionary that doesn’t explain modern usage and variation of usage probably means nothing for sociocultural analysis. But, if speakers of Scotts Gaelic went around talking about whiskey-tingling all the time, or if every mention of a person involved mentioning their hetero/homosexuality, _that_ would no doubt tell you something about (some parts of) the culture. But that’s _how a word is used_, or even _that a word is used_, not _that a word exists_. They’re not unrelated (duh), but quite different things.
Now, might one not make a distinction between the motivations behind the coinage of a word (or compound word; and I dare say that such motivations exist) and the ramifications (if any) of the widespread recognition and use of that word? In any field of study there is a special terminology, but the existence of those words (so long as they remain “terminology”) tells you not much other than that such a field exist(s/ed), and that some phenomena exist(s/ed) to be so named. But it’s not _nothing_. Some linguists do find it useful to explore the technological vocabulary that can be reconstructed for PIE, after all.
I’d say that the same goes for words with “expressive content” (to use Chris Potts’ term). The fact that words like “(a) homo” or “stingy” (compare “thrifty”) have attached to them some (let’s say) affective meaning says something at least about the sorts of stances taken towards sorts of activities. It says nothing about the culture as a whole (assuming such a thing exists), but the existence (and, potentially, persistence in everyday use) of the word can’t be taken as a mere accident of word coinage. [PS: one can always debate about the linguistic status of such content, I suppose]
In other cases, some coherent subculture may take to using a new word, or an old word with a different meaning, and then this word becomes used widely in the larger linguistic community (or maybe there were several steps in between). At each step, the reasons for adopting the word are no doubt complex and unknowable without a lot of time and mindreading abilities, and once a word like “gay” or whatever becomes widespread it probably doesn’t tell you anything about the culture of the linguistic community as a whole. If lexical-semantic change and spread is anything like phonetic change and spread, then the reasons for the existence of a word probably has little to do with the meaning per se and more to do with how speakers dealt with a new word – what social contexts in which to use it, how often to use it, etc. (NB: IANAS[ociophonetician]). But I’m open to the idea that lexical-semantic change and spread is actually lexical-semantically influenced — but not necessarily consciously. People surely pay attention to the meanings of the words they use, but if lexical semanticists have a job to do, most of the fine distinctions in meaning are inaccessible.