This chapter concerns the life-histories of lingua francas, languages adopted for communication among speakers who do not otherwise share a language. It recognizes four principal motives for developing a lingua franca: commerce, conquest, religious conversion, and cultural attraction. A lingua franca depends for its survival on the continuation in force of one or other of these motives, unless some user population adopts it as a mother-tongue, passing it on in the home, or dropping it for one purpose only to take it up afresh for another: this is Regeneration. Other paths, for decline of a lingua franca, include Ruin or Resignation, if the user community dissolves, and Relegation, if the use of the language is deliberately banned. In this framework, the careers of major languages (excluding European empires) are narrated: Akkadian, Aramaic, Greek in West Asia; Greek (again) and Latin in the Mediterranean and Europe; the sprouting and interaction of languages before European conquests in the Americas, and in Africa; Sanskrit, Persian, and later Malay in Southeast Asia, the interplay of Putonghua with other Chinese dialects across East Asia; and the rise of Hindi-Urdu in South Asia.