I've been considering the phenomenon of the lexical gap -- a concept for which no word exists. For example: what's the word for someone who is no longer a virgin?
See what I mean? English doesn't have one. You have to come up with some sort of conglomerate phrase to describe it (which, in the interests of keeping this blog PG-13 rated, I'm not going to do with the above example), but there's no single word that fits the concept.
Interestingly, there's a word for this phenomenon. Such gaps are called lacunae. They're holes in our mental naming system, and are not unique to English; all languages have lacunae of one sort or another. For example, did you know that Romanian has no word for "shallow?" They have to say "ape putsin adanci" ("not so deep waters"). But here's another one from English: in most languages, there's a generic word for a type of common animal, a different word for a male of the species, and a different word for a female. Thus: deer, stag, doe; horse, stallion, mare. What should go in the blank: ______, bull, cow?
Don't know? That's because there's no word in English that's a generic for that species. Oddly, we have a plural for it -- cattle -- but no singular!
Often other languages have words where we have lexical gaps. This is the subject of the delightful book The Meaning of Tingo, by Adam Jacot de Boinod, which goes into some whimsical examples of this phenomenon. The Maori, for example, have papakata, which is a name for a person with one leg shorter than the other. Then, there's the Japanese bakkushan, a word for a girl who looks pretty from behind, but when you see her from the front -- not so much. The German Backpfeiffengesicht means "a face that is just asking to have a fist in it." And tingo itself? It comes from the Pascuenese language of Easter Island, and means "to borrow things from someone's house, one by one, until there's nothing left."
Of course, those are some pretty esoteric concepts, and it may not be surprising that many languages lack words for them. However, there are some really peculiar lacunae -- holes in the lexicon for common concepts. I've always found it odd, for example, that standard English has no second person plural pronoun; you can mean either one person or more than one. It's one of the only languages I know that has this feature. Of course, southern English solves this neatly with the word y'all. You is one person; y'all is more than one. And in fact, in Louisiana English has a third form, for lots of people -- ALL y'all.
Of course, sometimes it's not that there's a lacuna, it's just that the word is really obscure. I have a positive affinity for weird little words that not many people know. For example, did you know that the little plastic things around the ends of your shoelaces are called aglets? Or that the groove between your nose and your upper lip is your philtrum? Or that an unlicensed liquor store is a shebeen? (At this point, you're probably guessing correctly that I'm a real pain in the ass to play the game "Dictionary" with.)
But back to lacunae. In some cases, we know what happened with the etymology that caused the hole. In the case of you, for example (not you personally) the form you used to be plural and polite only (comparable to the French vous); the singular and familiar form was thou. But in the 17th century, you became standard, and the use of thou was thought of as common and lacking in class. Finally thou was dropped altogether in favor of you, and we ended up with a hole.
In other cases, I don't think there's any real reason for the missing words. Why English has a word for someone who hasn't had sex yet, but no word for someone who has, is simply peculiar. Likewise, there being no singular form of cattle is simply an oddity of language evolution. Of course, given our propensity for borrowing words, we could probably fix some of these gaps by stealing words from other languages. (Myself, I know a few people who are seriously Backpfeiffengesicht, and would really like to use that word in describing them.) We could also take a page from the Norwegians' book and simply glue together old words to make new ones. They did that when the concept of "automobile accident" had to be covered -- by coining the word bilulykke, which literally means "car out of luck."
In any case, I predictably find the whole thing fascinating, and could probably blather on about it for quite a bit longer. But dinner's almost ready, and I'm really hungry -- and after all, I'm a nakkele (from the Tulu language of India) -- a guy who enjoys food so much that he licks the plate it was served on.