Ludwig Wittgenstein, an analytic philosopher of the twentieth century, discussed the origins of language in the second of his best-known works, Philosophische Untersuchungen ("Philosophical Investigations"). He borrowed a few lines from Augustine of Hippo, who had described his development of language as a process of finding the words to express the thoughts already in his mind, and then explored what language acquisition might look like among builders if words (simply) corresponded to objects.
Throughout the rest of this set of investigations, Wittgenstein illustrated that words are not so much in relationship to objects as they are pawns in language games, to be used variously according to how they fit given the various plays that have already been made. We understand one another because we've agreed on how to play with words.
I've reflected on Wittgenstein for years, but now I have children. Parenting and philosophizing meet at this moment in my life, especially today. MLKA, now eight months old, just signed "milk" for the first time. She hasn't yet spoken a word, but she can, when asked what she wants, move her fingers to open and close her fist, which is the ASL sign for milk. And now, newly endowed with linguistic agency (beyond the tones of her cries), she is able to be specific--this, not that. We don't have to work as hard to get what she wants. She has developed her first bodily signal to replace cries to indicate what she wants. Opening and closing a fist is an arbitrary action in itself, but we all have agreed in practice that "milk"--or, more particularly, our retrieving of milk in a bottle so she can drink it as soon as possible--is what that action means.
There will be more signs, and then spoken words, to replace her cries, and to give voice to her desires and fears and curiosities. I am excited for MLKA to explore the world on levels beyond that of bodily immediacy. That is our great gift as human beings, to be able reflectively to voice our experiences, giving those experiences new shades and memorability.