Mapping Language in the Age of GIS

Language mapping is a long-established cartographic practice, producing visual displays that are esthetically attractive and detailed but not replicable. They vary in scale, the mapped set of languages or language groups, and the strategy used to create a continuum of language. Today the assumption of a single dominant language over an extended and contiguous area of the Earth's surface, which underlies this traditional approach to language mapping, is challenged by largescale migration and the increasingly diverse nature of urban environments. The advent and growth of GIS over the past half century has been disruptive of many practices associated with maps and geospatial data. A process is described for the replicable production of language maps from raw data. Three use cases are identified and used to demonstrate the difficulties of addressing them with language maps and the ease with which they can be addressed using GIS. Many other more sophisticated use cases are readily addressed by GIS. The distribution of language in contemporary London provides a sharp contrast to traditional practices.