Proto-Germanic language

Proto-Germanic (PGmc; German Urgermanisch; also called Common Germanic, German Gemeingermanisch) is the reconstructed proto-language of the Germanic branch of the Indo-European family of languages.

Proto-Germanic developed into three branches during the first half of the 1st millennium AD: West Germanic, East Germanic and North Germanic, which however remained in contact over a considerable time, especially the North Sea Germanic group (including English), which arose from West Germanic dialects which remained in continued contact with North Germanic.

A defining feature of Proto-Germanic is the completion of the First Germanic Sound Shift. As it is probable that the development of this sound shift spanned a considerable time (several centuries), Proto-Germanic cannot adequately be reconstructed as a simple node in a tree model but rather represents a phase of development that may span close to a thousand years. The end of the Common Germanic period is reached with the beginning of the Germanic migrations in the 4th century AD.