Modern Standard German is a West Germanic language descended from the Germanic branch of the Indo-European languages. The Germanic languages are traditionally subdivided into three branches: North Germanic, East Germanic, and West Germanic. The first of these branches survives in modern Danish, Swedish, Norwegian, Faroese, and Icelandic, all of which are descended from Old Norse. The East Germanic languages are now extinct, and the only historical member of this branch from which written texts survive is Gothic. The West Germanic languages, however, have undergone extensive dialectal subdivision and are now represented in modern languages such as English, German, Dutch, Yiddish, Afrikaans, and others.
Within the West Germanic language dialect continuum, the Benrath and Uerdingen lines (running through Düsseldorf-Benrath and Krefeld-Uerdingen, respectively) serve to distinguish the Germanic dialects that were affected by the High German consonant shift (south of Benrath) from those that were not (north of Uerdingen). The various regional dialects spoken south of these lines are grouped as High German dialects (nos. 29–34 on the map), while those spoken to the north comprise the Low German/Low Saxon (nos. 19–24) and Low Franconian (no. 25) dialects. As members of the West Germanic language family, High German, Low German, and Low Franconian can be further distinguished historically as Irminonic, Ingvaeonic, and Istvaeonic, respectively. This classification indicates their historical descent from dialects spoken by the Irminones (also known as the Elbe group), Ingvaeones (or North Sea Germanic group), and Istvaeones (or Weser-Rhine group).
Standard German is based on Thuringian-Upper Saxon dialects (no. 30 on the map), which are Central German dialects (nos. 29–31), belonging to the Irminonic High German dialect group (nos. 29–34). German is therefore most closely related to the other languages based on High German dialects, such as Luxembourgish (based on Central Franconian dialects – no. 29), and Yiddish. Also closely related to Standard German are the Upper German dialects spoken in the southern German-speaking countries, such as Swiss German (Alemannic dialects – no. 34), and the various Germanic dialects spoken in the French region of Grand Est, such as Alsatian (mainly Alemannic, but also Central- and Upper Franconian (no. 32) dialects) and Lorraine Franconian (Central Franconian – no. 29).
After these High German dialects, standard German is (somewhat less closely) related to languages based on Low Franconian dialects (e.g. Dutch and Afrikaans) or Low German/Low Saxon dialects (spoken in northern Germany and southern Denmark), neither of which underwent the High German consonant shift. As has been noted, the former of these dialect types is Istvaeonic and the latter Ingvaeonic, whereas the High German dialects are all Irminonic; the differences between these languages and standard German are therefore considerable. Also related to German are the Frisian languages—North Frisian (spoken in Nordfriesland – no. 28), Saterland Frisian (spoken in Saterland – no. 27), and West Frisian (spoken in Friesland – no. 26)—as well as the Anglic languages of English and Scots. These Anglo-Frisian dialects are all members of the Ingvaeonic family of West Germanic languages which did not take part in the High German consonant shift.