How many languages are there? What differentiates one language from another? Are new languages still being discovered? Why are so many languages disappearing? These are some of the questions considered in this Very Short Introduction. By examining the science of languages, we find that the answers are not as simple as we might expect. Provides the basic facts about the world's major families of spoken languages and their distribution around the globe Relates to some of the big social issues facing the world today, such as bio-diversity and the endangerment of species and cultures Looks at the reasons behind why languages are declining, and why this really matters Raises the question about how we identify a language, and considers how we differentiate a 'language' from a 'dialect' Looks at signed languages and considers the similarities and differences to spoken language Part of the bestselling Very Short Introductions series - over five million copies sold worldwide