So, as I think I've noted before, I spend a good deal of time with a young child (YC). YC is just about 18 months and is learning vocabulary at lightening speed. She hears a word, she repeats a word, experiments with using it, pays attention to corrections and tries again. Seriously, we spend about 5 minutes in front of the refrigerator with her pointing to things, me saying what it was, her repeating, pointing to something else, saying something, me correcting, her pointing. It could have gone on all day, but I have a vague memory of my mother chastising me for standing in front of an open refrigerator for too long and so we ended the exercise.
Anyway, despite her learning very quickly and very accurately, YC insists upon calling the bird feeder 'mommy'. This has prompted me to theorize that she isn't using words the way that we (and she, ultimately, will) use words. She isn't using words to refer to objects in the world, but to something else — maybe the feelings she experiences when the words are being used in a way that she's learned is correct usage? The thing is that her mommy is the one who is in charge of the bird feeder at her house. So when she's pointing to the bird feeder and saying 'mommy' (and she does repeat 'bird feeder' when I say it, but then she says 'mommy' pretty soon after) she's not labelling the thing; she's got to be doing something else.
Gotta say I always (okay, almost always) hated philosophy of language (because no one has really be able to explain to me the point of it in a way that convinces me it matters), but if philosophy of language deals with stuff like this, I could completely get interested in it.