Common Brittonic, also known as British, Common Brythonic, or Proto-Brittonic, is an extinct Celtic language spoken in Britain and Brittany.

Old English, or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It developed from the languages brought to Great Britain by Anglo-Saxon settlers in the mid-5th century, and the first Old English literary works date from the mid-7th century. After the Norman Conquest of 1066, English was replaced for several centuries by Anglo-Norman as the language of the upper classes. This is regarded as marking the end of the Old English era, since during the subsequent period the English language was heavily influenced by Anglo-Norman, developing into what is now known as Middle English in England and Early Scots in Scotland.