British Latin or British Vulgar Latin was the Vulgar Latin spoken in Great Britain in the Roman and sub-Roman periods. While Britain formed part of the Roman Empire, Latin became the principal language of the elite and in the urban areas of the more romanised south and east of the island. In the less romanised north and west it never substantially replaced the Brittonic language of the indigenous Britons. In recent years, scholars have debated the extent to which British Latin was distinguishable from its continental counterparts, which developed into the Romance languages.

The settlement of Great Britain by diverse Germanic peoples, who eventually developed a common cultural identity as Anglo-Saxons, changed the language and culture of most of what became England from Romano-British to Germanic. This process principally occurred from the mid-fifth to early seventh centuries, following the end of Roman rule in Britain around the year 410. The settlement was followed by the establishment of the Heptarchy, Anglo-Saxon kingdoms in the south and east of Britain, later followed by the rest of modern England, and the south-east of modern Scotland. The exact nature of this change is a topic of on-going research. Questions remain about the scale, timing and nature of the settlements, and also about what happened to the previous residents of what is now England.