When I teach my introduction psychology course at Yale, I have a class on language. One of the things I do is this demonstration, I put this sentence up on the screen and then I walk through the class and there's about 400, 500 students, and I have the students who come from different countries, different societies say it in their native language. So I began I say it in English, "The girl thinks that the house is big," and the student say it in French, Spanish, Mandarin, and Turkish, Russian, Japanese. I go through two dozen languages, I have tried to get something as a sign language like American Sign Language along the scene Québécois. One thing which is obvious is that though this is a pretty abstract notion, all languages can express it. There are about 6,000 spoken languages in the world and many other sign languages and nobody says, "Well, I can't say that in my language." Languages share their extraordinary expressive power. On the other hand, something which is also obvious is the languages are different, they sound different. I know English, I know a little bit of French, a little bit of Spanish, but the rest of the languages are incomprehensible to me and to most other students in the class. So a Korean speaker can say this perfectly, but, and this is kind of obvious, an English speaker doesn't understand it. So, what can we say about languages, about the power of languages and how languages are different in what they have in common? Well, one observation comes from Charles Darwin who wrote, man has an instinctive tendency to speak as we see in the babble of our young children, while no child has an instinctive tendency to bake, brew, or write." What Darwin is saying here is that language is special, language is something which is instinctive and as such differs from other human capacities like baking or brewing or writing, and here Darwin is making a distinction between language and its natural modality of speech and as we'll see sign versus reading and writing which really is unnatural and needs to be learned. Every human society has language, fitting with Darwin's idea that language is instinctive and natural, it shows up everywhere. Humans have come across other societies which lack architecture, where people don't wear much clothing, where all sorts of technology that some societies have these societies lack. But humans have never stumbled across another group of humans which lack language, language is universal. Now, this doesn't show that languages is instinctive or that is built into the brain. Because language might have even been invented once and spread through history. I think right now, it's going to be very hard to find a society that lacks soccer or Coca-Cola. But that's not because soccer and Coca-Cola aren't distinctive, it's because soccer and Coca-Cola were thought up at one point and then spread through the world. Maybe language is like this, but there's good reason to believe that it's not and that Darwin is right. One interesting source of evidence here is a phenomenon known as creolization, and so creolization in its standard case involves people who are involved in the slave trade, the production of tobacco, cotton, coffee, sugar who would bring together and mix slaves and laborers from different language backgrounds. So these people would work together but they didn't have a common language. What often happens is they develop a makeshift jargon which is called a pidgin, P-I-D-G-I-N which involve strings of words borrowed from the language of the plantation owners, often from people's own native tongues. But there's no word or no grammar, imagine yourself locked in a room working with a bunch of people with no common language, but you had to work together so you'd make a sort of common communication system. Now, the question which arises is, the children in these societies, the children of the slaves were often brought up independently from their parents in a collective setting and what they heard was mostly a pidgin, and so the question is what would they come to know? And you might imagine well, you're exposed to a pidgin, you'll learn a pidgin. But this isn't actually what happens. What's interesting is children are built so that they take this non-linguistic system as rudimentary system and transform it into a real language with syntax and morphology and phonology and we'll learn what these are in a second. But a real language, which is known as creole. So when you hear about a creole now of which many people speak, that remarks in this historical origin of creole was once a pidgin and has been transformed into a language and that tells us something about the human mind. There are actually some modern cases of creolization that had been studied. So imagine a child who is born deaf to hearing parents, so the parents understandably enough want to communicate with the child so they quickly learn a sign language through which to communicate with the child but they're not, because it's second language learning which is difficult. The language that the parents use is more of a pidgin and children are exposed to a pidgin. But what often happens particularly if children are raised in a community of other children in the same situation? Is that they creolize, they take this simple communication system that they're exposed to and they transform it into a full-blown language. This is interesting, this tells us something about our capacity and our expectations with regard to language. Furthermore, just as every normal society has language, every normal human has language. This is true by definition if a child reaches the age of three or four and doesn't speak, there's a serious problem going on which requires serious attention and that's different from other things. Not everybody knows chess or rides a bicycle, but language seems to be the sort of thing that everybody comes to possess. It's no surprise then that there are specific areas in the brain that are devoted to language. We'll talk a little bit more about these later on in the course. What's a little more controversial is what these brain areas do and these genes cause. There's no doubt that humans have a special capacity for language, but the precise nature of this capacity whether it's something specific and designed for language or whether it's a more general set of capacities that allow people to learn language that's a matter of controversy. So, what else can we say about language? Well, when linguists talk about language, they say that language has the property of creativity and this can mean different things, it creative, is often used to describe special abilities and that's not what we're talking about here. We're meaning, that normally, for normal use of language, people can say what they choose to say and can produce a virtually infinite number of sentences by one estimate, the number of sentences under 20 words long is 1 with 30 zeros after it. So if it took you five seconds to say a sentence, in order to say all of them you'd have to spend about 100 trillion years. I asked students to stand up and say a sentence that nobody in the history of the universe has ever said before. I'll say one myself, "I saw an episode of TV show Black Mirror last night and it was quite haunting though I have to say that the ending was a little bit predictable given some foreshadowing early on involving some treatment of out groups and some hints at a powerful technology." It's not the greatest sentence in the world maybe it's not so interesting but you understand it and you've never heard it before. This suggests that language understanding, language comprehension, language production, can't just be a matter of rote memory. If you understood what I said and understand I'm saying now, it can't be because at some point you've memorized the meanings of these sentences, you have to have some way of taking strings of words that are put together in order you've never heard before and making sense out of them. So how do we do this? Well, we do this through rules and principles. We have these abstract and unconscious rules in our heads that let us take strings of words and make sense of them. When I'm talking about rules of language, I'm not talking about things like don't say ain't or don't end a sentence with a preposition, these are not rules that you're forced to comply within school, they're not what linguists call prescriptive rules which is how you should use language, rather these are abstract and unconscious rules that you have. You don't even know you have them that allow you to figure out the virtually infinite strings of sentences you could be exposed to. These are what the things that linguists study. So for instance, you hear a sentence, "The pig is eager to eat," and instinctively, immediately in a fraction of a second, you understand that the eating here is to be done by the pig. But if you hear a sentence, "The pig is easy to eat," in the same fraction of a second you realize this means that the eating is of the pig not by the pig. Or take a sentence, "Bill knew John liked him." Any speaker of English realizes that this could mean that Bill knew John liked Bill, it could have other meanings but it could mean that Bill knew John like Bill. But if you hear the sentence, "Bill knew that John liked himself." This can't mean that Bill knew that John liked Bill, it has to mean that Bill knew that John liked John. If this is the sort of thing that fascinates you and you have this tremendous hunger to work out the rules explaining how we do this, what rules are working, how do you characterize them best, how many of them are universal. Then you may well decide you want to devote your life to becoming a linguist because that's what linguists do and to me this is one of the coolest enterprises ever. So, we characterize languages in terms of these rules and principles and it turns out that language can be characterized at different levels. You can talk about the sound system of language phonology, you can have about words and how words are composed, morphology, and you could talk about how words are combined to make phrases and sentences which is syntax, and I'm going to talk about these three things in turn.