We live in modern Babylon. In Europe, more languages are spoken today than ever before. At no other time have so many different cultures been in contact with each other. However, modern multilingualism in Europe is just a small snapshot of the linguistic and cultural diversity of the world, which has around 6,400 different languages. This lexicon describes the most important languages and language families in about 250 articles, in a concise and easily understandable manner. It includes almost all languages with more than one million speakers, the most well-known smaller languages (such as Basque or Frisian), a representative selection of minority languages with fewer than 1,000 speakers (such as Livonian or Ainu), as well as some extinct languages (such as Latin or Sumerian) that have influenced our modern linguistic and cultural heritage. The articles provide information on the number of speakers and the geographical distribution of the languages, their affiliation to language families, differences between written language, colloquial language, and dialects, grammatical structures, composition of the vocabulary, writing systems, and language history.