High German consonant shift in the context of "German dialects"

Old High German (OHG; German: Althochdeutsch (Ahdt., Ahd.)) is the earliest stage of the German language, conventionally identified as the period from around 500/750 to 1050. Rather than representing a single supra-regional form of German, Old High German encompasses the numerous West Germanic dialects that had undergone the set of consonantal changes called the Second Sound Shift.

At the start of this period, dialect areas reflected the territories of largely independent tribal kingdoms, but by 788 the conquests of Charlemagne had brought all OHG dialect areas into a single polity. The period also saw the development of a stable linguistic border between German and Gallo-Romance, later French.

Low German is a West Germanic language spoken mainly in Northern Germany and the northeastern Netherlands. The dialect of Plautdietsch is also spoken in the Russian Mennonite diaspora worldwide. "Low" refers to the altitude of the areas where it is typically spoken.

Low German is most closely related to Frisian and English, with which it forms the North Sea Germanic group of the West Germanic languages. Like Dutch, it has historically been spoken north of the Benrath and Uerdingen isoglosses, while forms of High German (of which Standard German is a standardized example) have historically been spoken south of those lines. Like Frisian, English, Dutch and the North Germanic languages, Low German has not undergone the High German consonant shift, as opposed to Standard High German, which is based on High German dialects. Low German evolved from Old Saxon (Old Low German), which is most closely related to Old Frisian and Old English (Anglo-Saxon).

The First Schleswig War (German: Schleswig-Holsteinischer Krieg), also known as the Schleswig-Holstein uprising (German: Schleswig-Holsteinische Erhebung) and the Three Years' War (Danish: Treårskrigen), was a military conflict in southern Denmark and northern Germany rooted in the Schleswig–Holstein question: who should control the Duchies of Schleswig, Holstein and Lauenburg, which at the time were ruled by the king of Denmark in a personal union. Ultimately, the Danish side proved victorious with the diplomatic support of the great powers, especially Britain and Russia, since the duchies were close to an important Baltic seaway connecting both powers.

While Schleswig had been predominantly Danish with a German elite concentrated in the cities and estates, modernisation brought extensive German influence. German became the language of administration, education, and the church, creating an environment in which it was omnipresent and speaking Danish offered no advantages. Due to top-down pressure, many Danish South Schleswigers gradually adopted German in their daily lives. This linguistic shift led to the extinction of the two Danish South Schleswig dialects, Fjoldemål and Angeldanish – first in favour of Low German, and later High German. Over time, these now Low German-speaking South Schleswigers became fully Germanized, came to identify with the German question, and sought to separate Schleswig, along with Holstein, from Denmark entirely. Therefore, by the outbreak of the war, Schleswig was divided: a Danish-speaking North and a Low German-speaking South, while Holstein and Lauenburg were entirely ethnically German.

The High German languages (German: hochdeutsche Mundarten, i.e. High German dialects), or simply High German (Hochdeutsch [ˈhoːxˌdɔɪ̯t͡ʃ] ) – not to be confused with Standard High German which is commonly also called "High German" – comprise the varieties of German spoken south of the Benrath and Uerdingen isoglosses, i.e., in central and southern Germany, Austria, Liechtenstein, Switzerland, Luxembourg, and eastern Belgium, as well as in neighbouring portions of France (Alsace and northern Lorraine), Italy (South Tyrol), the Czech Republic (Bohemia), and Poland (Upper Silesia). They are also spoken in diasporas in Romania, Russia, Canada, the United States, Brazil, Argentina, Mexico, Chile, and Namibia.

High German is marked by the High German consonant shift, separating it from Low German (Low Saxon) and Low Franconian (including Dutch) within the continental West Germanic dialect continuum. "Low" and "high" refer to the lowland and highland geographies typically found in the two areas.

Middle High German (MHG; endonym: diutsch or tiutsch; New High German: Mittelhochdeutsch [ˈmɪtl̩hoːxˌdɔʏtʃ] , shortened as Mhdt. or Mhd.) is the term for the form of High German spoken in the High Middle Ages. It is conventionally dated between 1050 and 1350, developing from Old High German (OHG) into Early New High German (ENHG). High German is defined as those varieties of German which were affected by the Second Sound Shift; the Middle Low German (MLG) and Middle Dutch languages spoken to the North and North West, which did not participate in this sound change, are not part of MHG.

While there is no standard MHG, the prestige of the Hohenstaufen court gave rise in the late 12th century to a supra-regional literary language (mittelhochdeutsche Dichtersprache) based on Swabian, an Alemannic dialect. This historical interpretation is complicated by the tendency of modern editions of MHG texts to use normalised spellings based on this variety (usually called "Classical MHG"), which make the written language appear more consistent than it actually is in the manuscripts. Scholars are uncertain as to whether the literary language reflected a supra-regional spoken language of the courts.

In German linguistics, the Benrath line (German: Benrather Linie) is the maken–machen isogloss: dialects north of the line have the original /k/ in maken (to make), while those to the south have the innovative /x/ (machen). The line runs from Aachen in the west via Benrath (south of Düsseldorf) to eastern Germany near Frankfurt an der Oder in the area of Berlin and Dessau and through former East Prussia dividing Low Prussian dialect and High Prussian dialect. It is called Benrath line because Benrath is the place where it crosses the Rhine.

The High German consonant shift (3rd to 9th centuries AD), in which the (northern) Low German dialects for the most part did not participate, affected the southern varieties of the West Germanic dialect continuum. This shift is traditionally seen to distinguish the High German varieties from the other West Germanic languages.