This lecture is about language. And from a theoretical standpoint, language is where the action is. If you have a theory about the mind and how it works, you would better explain language. And different theories are assessed and judged on how well they succeed at capturing this astonishing human capacity. Whether we're talking about philosophers like Aristotle, Plato, Hume, Locke, psychologists like Freud and Skinner, modern day approaches that computational analysis or cognitive nerve science, evolutionary theory, cross cultural psychology, if you can't explain language, you're not in the game. And language is so significant that there is an entire field devoted to its study, the field of linguistics. And although this is not a linguistics course, it's impossible to talk seriously about language, and the psychology of language without delving into some extent to the science of linguistics. Now, I first want to get into a terminological point. What do I mean by language? And when I talk about language, at least for this beginning phase, I mean systems like English and Dutch and French and Navajo and Mandarin and so on. Now, you could use language in other ways. You could use the word language to describe animal communication or music or any communication system you want. And there's nothing wrong with this. I hate terminological arguments. People are free to use language any way they choose. But from a scientific purpose, when we discuss language and how it's learned and how it's encoded in the brain, we have to be clear what we're talking about. And as a starting point I want to talk about this more restricted version, the sorts of things that people use exclusively from day to day life, both spoken languages like English and sign languages like American Sign Language. And once we come to some insight about how all of that works, we could then step back and then see whether the same principles we find for those languages in a restrictive sense apply to music, or to a bird song, or to art and whatever. Before proceeding, I want to do something which I haven't been doing in the other lectures. I want to recommend a couple of books. I want to recommend The Language Instinct by Steven Pinker, which is a classic introduction to the science of language. And one reason why I want to give it this shout out is that some of my examples that follow and some of my analyses are going to be based on his book. So this is crediting him with this. I also want to recommend John McWhorter's book, The Power of Babel, which takes a somewhat different approach than Pinker and looks more at language as a historical artifact, how it changes over time. Less psychology, less evolution, but a lot more history, and they're both wonderful books.