Within the Indo-European family tree, surviving languages show various degrees of similarity due to their common origin, bearing a more or less direct relationship to their geographical distribution. They fall into eleven different groups: Indian, Iranian, Armenian, Hellenic, Albanian, Italic, Balto-Slavic, Germanic, Celtic, Hittite and Tocharian.
Germanic, which antedates the first written records, can be divided into three branches: East Germanic, North Germanic and West Germanic.
East Germanic comprises languages such as Gothic – which accounts for the first written record of Germanic, in the shape of runes in Scandinavia – Burgundian and Vandalic.
North Germanic, which gave way to Old Norse, or early Scandinavian and from which two branches grow out of dialectal differences; on to the East, developing into Swedish and Danish and the other to the West, developing into Norwegian and Icelandic -the most literary of all, with an important body of heroic literature such as the Elder or Poetic Edda compiled by Snorri Sturluson (12th-13th centuries) -.
Finally, there is West Germanic, to which English belongs, and which separates in High German and Low German due to the operation of the 2nd Sound Shift, by which West Germanic voiceless plosives /p, t, k/ and voiced plosive /d/ changed into other sounds in AD 600 in the southern mountainous Germanic area, but not in the lowlands (North). This phenomenon of unknown origin is often assumed to have its origin in the contact with non-Germanic population due to the migration of foreign tribes into Germanic territory.
Thus, High German is the origin of Rhenish, East Franconian, Bavarian and Alemannic, and Low German divides into Old Saxon (essential constituent of Plattdeutsch), Old Low Franconian (basisfor Dutch and Flemish), Old Frisian and finally, OLD ENGLISH.
Old English is not entirely uniform, though. It comprises four dialects: Northumbrian, Mercian – each bearing their distinctive features and their common ones -, West Saxon and Kentish. Nearly all Old English literature preserved in manuscripts come from West Saxon, which attained the position of literary standard and was eventually cut short by the Norman invasions, giving way to a standard based on the dialect used in the East Midlands.