Old English
Old English refers to the English language as it was from about the middle of the fifth century until around the middle of the twelfth century.
In the fifth century, significant numbers of Angles, Saxons and Jutes from Northern Europe arrived in England. The invaders dominated the original Celtic-speaking inhabitants, whose languages survive largely in Scotland, Wales, and Cornwall. The dialects spoken by the invaders formed what is now called Old English. Later, it was strongly influenced by the North Germanic language Norse, spoken by the Vikings who invaded and settled mainly in the north-east of England (see Jórvík and Danelaw). The new, and the earlier, settlers spoke languages from different branches of the Germanic family; many of their lexical roots were the same or similar, although their grammars were more distinct, including the prefix, suffix and inflection patterns for many of their words. The Germanic language of these Old English speaking inhabitants of Britain was influenced by contact with Norse invaders, which may have been responsible for some of the morphological simplification of Old English, including loss of grammatical gender and explicitly marked case (with the notable exception of the pronouns). The most famous surviving work from the Old English period is a fragment of the epic poem "Beowulf", by an unknown poet, though substantially modified, likely by one or more Christian clerics long after its composition.
There were several major dialect areas of Old English: Northumbrian in the north, Kentish in the southeast, West Saxon in the southwest, and Mercian in the central Midlands region. Although Mercian is the most direct ancestor of Modern English, few documents survive in it; the vast majority of written materials are in West Saxon, which functioned as the prestige dialect because it was the speech of the Saxon seat of power at Winchester.
Old English had no written form (aside from the occasional use of runes) until the introduction of Christianity; with it came a relatively phonetic alphabetic system, as well as loanwords from Latin and some Greek. Danish incursions along the Eastern coasts created an area of influence known as the Danelaw, and Danish had a substantial influence, particularly on the pronoun system. The Old English period formally ended with the Norman conquest, when the language was influenced, to an even greater extent, by the Norman French-speaking Normans.