Old English

Old English (also called Anglo-Saxon) is an early form of the English language that was spoken in parts of what is now England and southern Scotland between the mid­ fifth century and the mid-twelfth century. It is a West Germanic language and therefore is closely related to Old Frisian and Old Saxon. It also experienced heavy influence from Old Norse, a member of the related North Germanic group of languages. It is also closely related to German and Dutch.

450 -1100 Old English (Anglo-Saxon) - The language of Beowulf.

1100 -1500 Middle English - The language of Chaucer.

1500 - 1650 Early Modem English (or Renaissance English) - The language of Shakespeare.

1650 - present Modern English (or Present-Day English) - The language as spoken today.

Development
         Old English was not static, and its usage covered a period of approximately 700 years ­- from the Anglo - Saxon migrations that created England in the fifth century to some time after the Norman invasion of 1066, when the language underwent a major and dramatic transition. During this early period it assimilated some aspects of the languages with which it came in contact, such as the Celtic languages and the two dialects of Old Norse, from the invading Vikings, who were occupying and controlling large tracts of land in northern and eastern England, which came to be known as the Danelaw.

Dialects
Old English had many dialects. The four main dialect forms of Old English were Mercian, Northumbrian (known as Anglian), Kentish, and West Saxon. Each of these dialects was associated with an independent kingdom on the island. Of these, all of Northumbria and most of Mercia were overrun by the Vikings during the 9th century.

After the process of unification of the diverse Anglo- axon kingdoms in 878 by Alfred the Great, there is a marked decline in the importance of regional dialects. 
However, the bulk of the surviving documents from the Anglo-Saxon period are written in the dialect of Wessex, Alfred's kingdom. It seems likely that with consolidation of power, it became necessary to standardise the language of government to reduce the difficulty of administering the more remote areas of the kingdom.
Literature
Old English was one of the first vernacular languages to be written down. Some of the most important surviving works of Old English literature are Beowulf, an epic poem; the Anglo-Saxon Chronicle, a record of early English history; and Caedmon's Hymn, a Christian religious poem. There are also a number of extant prose works, (sermons and saints' lives, biblical translations, legal documents, and practical works on grammar, medicine, and geography). Poetry is considered to be the heart of Old English literature. Nearly all Anglo-Saxon authors are anonymous, with a few exceptions, such as Bede and Caedmon.
Orthography
Old English was at first written in runes, but shifted to the Latin alphabet, with some additions, after the Anglo-Saxons' conversion to Christianity.

Germanic origins
The most important force in shaping Old English was its Germanic heritage in its vocabulary, sentence structure and grammar which it shared with its sister languages in continental Europe. Some of these features were specific to the West Germanic language family to which Old English belongs, while some other features were inherited from the Proto-Germanic language.Like other West Germanic languages of the period, Old English was fully inflected with five grammatical cases (nominative, accusative, genitive, dative, instrumental). It also assigned gender to all nouns, including those that describe inanimate objects: for example, seo sunne (the Sun) was feminine, while se mona (the Moon) was masculine.
Latin influence 
A large percentage of the educated and literate population (monks, clerics, etc.) were competent in Latin, which was the lingua franca of Europe at the time. There were at least three notable periods of Latin influence. The first occurred before the ancestral Saxons left continental Europe for England. The second began when the Anglo-Saxons were converted to Christianity and Latin-speaking priests became widespread. The third and largest single transfer of Latin-based words occurred following the Norman invasion of 1066, after which an en6rmous number of Norman words entered the language. The Norman Conquest approximately marks the end of Old English and the advent of Middle English.

Viking influence
The second major source of loanwords to Old English were the Scandinavian words introduced during the Viking invasions of the ninth and tenth centuries. In addition to a great many place names, these consist mainly of items of basic vocabulary, and words concerned with particular administrative aspects of the Danelaw (that is, the area of land under Viking control, which included extensive holdings all along the eastern coast of England and Scotland). The Vikings spoke Old Norse, a language related to Old English in that both derived from the same ancestral Proto-Germanic language. The influence of Old Norse on the English language has been profound: responsible for such basic vocabulary items as sky, leg, and the modern pronoun they, among hundreds of other words.
  
Celtic influence
It has traditionally been maintained that the influence of Celtic on English has been small, citing the small number of Celtic loanwords taken into the language. The number of Celtic loanwords is lower than either Latin or Scandinavian.