 Welcome to this brief introduction to what is a corpus. A corpus is a collection of texts and it is quite large. It is millions or very often these days, billions of words, but it's not just a random collection of words. It is a representative collection of samples of a whole language of a genre, or a period, or a subject in the language. There are a corpora of many languages, English, Czech, Russian, French, and so on, but there are also corpora of different parts of a language. There is a corpus of historical English, of journalistic English, of academic English, and so on, but there are even more specialized corpora, for example, corpora of child language or a corpus of student writing. There are of course also corpora of spoken languages such as English and parallel translations between languages where you can compare how different words and phrases and expressions are translated. The most important thing about a corpus is that it is searchable and you can use a special language to discover what is happening with language. So, for example, you can search for different forms of a word and then see that word in context, see how it is used in actual real language. Linguists use corpora to research the structure of language. It is an essential tool these days but they also use it to find out how language is actually used rather than how we think it should be used and then these findings can be used to build new better grammars and better dictionaries. Sociologists can also use a corpus, for example, to study how people express their preferences and values in different contexts. Sociologists can also use this to create better survey questions that are more understandable based on how people are likely to have seen language being used and that's another way that psychologists can also take advantage of a corpus because they can use it to help them create more representative experimental questions. Historians can look at a corpus to see reactions to past events through different periods of time and they can also do the same thing as sociologists and study how people have expressed their preferences and values in different periods. But a corpus can also be used in a very practical way. For example, writers can use it to just find out how words and phrases are actually used by different writers and find inspirations and also avoid certain ways of expressing themselves. Teachers of languages can use a corpus by helping them prepare better exercises and again making sure that they're using exercises with language that the students will actually need to use and they can also expose their students to a corpus to help them see language in a realistic context and students themselves can then take advantage of having access to a corpus and see how words are used in for example in academic English or in another context. So if you'd like to get started now you can go to EnglishCorpra.org and start searching. Look at the different ways of finding out things about English. If you'd like to find out more about the corpus and also about corpora in other languages, join our workshop at the IT Learning Center at Oxford and best of luck with your corpus use and hope to see you there.