Old English is a West Germanic language, developing out of Ingvaeonic (also known as North Sea Germanic) dialects from the 5th century. It came to be spoken over most of the territory of the Anglo-Saxon kingdoms which became the Kingdom of England. This included most of present-day England, as well as part of what is now southeastern Scotland, which for several centuries belonged to the Anglo-Saxon kingdom of Northumbria. Other parts of the island – Wales and most of Scotland – continued to use Celtic languages, except in the areas of Scandinavian settlements where Old Norse was spoken. Celtic speech also remained established in certain parts of England: Medieval Cornish was spoken all over Cornwall and in adjacent parts of Devon, while Cumbric survived perhaps to the 12th century in parts of Cumbria, and Welsh may have been spoken on the English side of the Anglo-Welsh border. Norse was also widely spoken in the parts of England which fell under Danish law.
Try to answer this question if possible (otherwise reply "unanswerable"): What language was spoken in Cornwall?
Medieval Cornish