South Jutland County in the context of "Nordfriesland (district)"

German (Deutsch, pronounced [dɔʏtʃ] ) is a West Germanic language in the Indo-European language family, mainly spoken in Western and Central Europe. It is the majority and official (or co-official) language in Germany, Austria, Switzerland, and Liechtenstein. It is also an official language of Luxembourg, Belgium and the Italian autonomous province of South Tyrol, as well as a recognized national language in Namibia. There are also notable German-speaking communities in other parts of Europe, including: Poland (Upper Silesia), the Czech Republic (North Bohemia), Denmark (North Schleswig), Slovakia (Krahule), Romania, Hungary (Sopron), and France (Alsace). Overseas, sizeable communities of German-speakers are found in the Americas.

German is one of the major languages of the world, with nearly 80 million native speakers and over 130 million total speakers as of 2024. It is the most spoken native language within the European Union. German is the second-most widely spoken Germanic language, after English, both as a first and as a second language. German is also widely taught as a foreign language, especially in continental Europe (where it is the third most taught foreign language after English and French) and in the United States (where it is the third most commonly learned second language in K-12 education and among the most studied foreign languages in higher education after Spanish and French). Overall, German is the fourth most commonly learned second language globally. The language has been influential in the fields of philosophy, theology, science, and technology. It is the second most commonly used language in science and the third most widely used language on websites. The German-speaking countries are ranked fifth in terms of annual publication of new books, with one-tenth of all books (including e-books) in the world being published in German.

Schleswig-Holstein (/ˈʃlɛswɪɡ ˈhoʊlstaɪn/; German: [ˌʃleːsvɪç ˈhɔlʃtaɪn] ; Danish: Slesvig-Holsten [ˌsle̝ːsvi ˈhʌlˌste̝ˀn]; Low German: Sleswig-Holsteen; North Frisian: Slaswik-Holstiinj; occasionally in English Sleswick-Holsatia) is the northernmost of the 16 states of Germany, comprising most of the historical Duchy of Holstein and the southern part of the former Duchy of Schleswig. Its capital city is Kiel; other notable cities are Lübeck and Flensburg. It covers an area of 15,763 km (6,086 sq mi), making it the 5th smallest German federal state by area (including the city-states). Historically, the name can also refer to a larger region, containing both present-day Schleswig-Holstein and the former South Jutland County (Northern Schleswig; now part of the Region of Southern Denmark) in Denmark.

Schleswig, known as South Jutland at the time, had been under Danish control since the fifth century. In the 12th century, however, it became a duchy within Denmark due to infighting in the Danish royal house. It bordered Holstein, which was a part of the Holy Roman Empire. Beginning in 1460, the King of Denmark ruled both Schleswig and Holstein as their duke. Schleswig was still part of Denmark, while Holstein remained part of the Holy Roman Empire. In the 19th century, both Danes and Germans believed they had a rightful claim to Schleswig-Holstein. While the population of Holstein and Lauenburg was entirely ethnically German, Schleswig had been predominantly Danish until the late 1700s and early 1800s, when extensive German influence led to the Germanization of South Schleswig. The resulting long-term political and territorial dispute was known as the Schleswig-Holstein Question. In 1848, Denmark tried to formally annex the area. Prussia responded by invading, thus beginning the First Schleswig War, which ended in a victory for Denmark. But in the Second Schleswig War (1864), Prussia and Austria won, and the territory was absorbed into Prussia in 1867. After the German defeat in World War I the Allies required that the question of sovereignty over the territory be submitted to plebiscites (the 1920 Schleswig plebiscites). They resulted in the return of the Danish-speaking North Schleswig to Denmark. The area was subsequently renamed South Jutland, restoring the historical name used before it was changed to Schleswig by Gerhard III of the House of Schauenburg. After World War II, Schleswig-Holstein took in over a million refugees.

Jutland (/ˈdʒʌtlənd/), historically known as the Cimbrian Peninsula, is a peninsula in Northern Europe that forms the continental portion of Denmark and part of northern Germany (Schleswig-Holstein). It stretches from the Grenen spit in the north to the confluence of the Elbe and the Sude in the southeast. The historic southern border river of Jutland as a cultural-geographical region, which historically also included Southern Schleswig, is the Eider. The peninsula, on the other hand, also comprises areas south of the Eider: Holstein, the former duchy of Lauenburg, and most of Hamburg and Lübeck.

Jutland's geography is flat, with comparatively steep hills in the east and a barely noticeable ridge running through the center. West Jutland is characterised by open lands, heaths, plains, and peat bogs, while East Jutland is more fertile with lakes and lush forests. The southwestern coast is characterised by the Wadden Sea, a large, unique international coastal region stretching through Denmark, Germany, and the Netherlands. The peninsula's longest river is the Eider, which rises close to the Baltic but flows in the direction of the North Sea due to a moraine, while the Gudenå is the longest river of Denmark. In order for ships not having to go around the whole peninsula to reach the Baltic, the Kiel Canal – the world's busiest artificial waterway, crossing the peninsula in the south – was constructed.

The Duchy of Schleswig (/ˈʃlɛswɪɡ/; German: [ˈʃleːsvɪç]; Danish: Hertugdømmet Slesvig; German: Herzogtum Schleswig; Low German: Hartogdom Sleswig; North Frisian: Härtochduum Slaswik) was a duchy in Southern Jutland (Sønderjylland) covering the area between about 60 km (35 miles) north and 70 km (45 mi) south of the current border between Germany and Denmark. The territory has been divided between the two countries since 1920, with Northern Schleswig in Denmark and Southern Schleswig in Germany. The region is also called Sleswick in English.

Unlike Holstein and Lauenburg, Schleswig was never a part of the German Confederation. Schleswig was instead a fief of Denmark, and its inhabitants spoke Danish, German, and North Frisian. Both Danish and German National Liberals wanted Schleswig to be part of a Danish or German national state in the 19th century. A German uprising in March 1848 caused the First Schleswig War which ended in 1852. The Second Schleswig War (1864) ended with the three duchies being governed jointly by Austria and Prussia. In 1866, they became a part of Prussia.

Southern Schleswig (German: Südschleswig or Landesteil Schleswig, Danish: Sydslesvig; North Frisian: Söödslaswik) is the southern half of the former Duchy of Schleswig in Germany on the Jutland Peninsula. The geographical area today covers the large area between the Eider river in the south and the Flensburg Fjord in the north, where it borders Denmark. Northern Schleswig, congruent with the former South Jutland County, forms the southernmost part of Denmark. The area belonged to the Crown of Denmark until Prussia and Austria declared war on Denmark in 1864. Denmark wanted to give away the German-speaking Holsten and set the new border at the small river Ejderen. Prussian chancellor Otto von Bismarck concluded that this justified a war, and even proclaimed it a "holy war". He also turned to the Emperor of Austria, Franz Joseph I of Austria for help. A similar war in 1848 had gone poorly for the Prussians. With Prussia's modern weapons and the help from both the Austrians and General Moltke, the Danish army was destroyed and forced to make a disorderly retreat. The Prussian-Danish border was then moved from the Elbe up in Jutland to the Kongeåen creek.

After the First World War, two referendums decided a new border.The northern part reverted to Denmark as Nordslesvig (North Slesvig). But the middle and southern part, including Schleswig's only city, Flensburg, remained in Germany. In Denmark, the loss of Flensborg sparked a political crisis, Påskekrisen or the Easter Crisis of 1920. After the Second World War the area remained as German territory and, with Holstein, formed the new state of Schleswig-Holstein as a part of the Federal Republic of Germany (West Germany) in 1948.

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.