It is no coincidence that humans are special in their ability to outsmart other animals and plants by cause-and-effect reasoning, and that language is a way of converting information about cause-and-effect and action into perceptible signals. A distinctive and important feature of information is that it can be duplicated without loss. (If I give you a fish, I do not have the fish,but if I tell you how to fish, it is not the case that I now lack the knowledge how to fish.) A species that has evolved to rely on information should thus also evolve a means to exchange that information. Language multiplies the benefit of knowledge, because a bit of know-how is useful not only for its practical benefits to oneself but as a trade good with others. Using language, a person can exchange knowledge with somebody else at a low cost to himself and hope to get something in return. It can also lower the original acquisition cost—people can learn, say, how to catch a rabbit from someone else’s trial and error, without having to go through it themselves.
What struck me was the importance of metaphor in abstract reasoning. If I say (about a chess game) that "I was forced to move my king," it does not mean that I was physically forced, but everyone understands the metaphor.
Thus, I would say that for a computer, understanding language is not just a matter of building up a knowledge base. It's a harder problem. I wrote on artificial intelligence here.