Blurb:

When different communities are in contact, they often resort to a lingua franca, a kind of ‘bridge’ language that is distinct from the mother tongues of each group. People learn lingua francas deliberately, in order to achieve some purpose; this means that a lingua franca's fate in the long term is vulnerable to changes in the balance of wealth and power. Along with the current example of English, past examples of Classic Chinese, Persian, Latin, French, and Spanish are discussed.