Middle High German (German: Mittelhochdeutsch), abbreviated MHG (Mhd.), is the term used for the period in the history of the German language between 1050 and 1350. It is preceded by Old High German and followed by Early New High German. In some uses, the term covers a longer period, going up to 1500.
Middle High German is not a unified written language and the term covers two main dialect areas:
The Middle Low German and Middle Dutch areas in the North are not covered by 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. However, the picture is complicated by the fact that modern editions of MHG texts have a tendency to use normalised spellings based on this variety (usually called "Classical MHG"), which make the written language appear more consistent than is actually the case in the manuscripts. It is uncertain whether the literary language reflected a supra-regional spoken language of the courts.
The High German languages (in German, Hochdeutsche Sprachen) or the High German dialects (Hochdeutsche Mundarten/Dialekte) are any of the varieties of standard German, Luxembourgish and Yiddish, as well as the local German dialects spoken in central and southern Germany, Austria, Liechtenstein, Switzerland, Luxembourg and in neighboring portions of Belgium and the Netherlands (Ripuarian dialects in southeast Limburg), France (Alsace and northern Lorraine), Italy, Denmark, and Poland. The language is also spoken in diaspora in Romania (Transylvania), Russia, the United States, Brazil, Argentina, Chile, and Namibia.
As a technical term, the "high" in High German is a geographical reference to the group of dialects that forms "High German" (in the broader sense), out of which developed standard High German (in the narrower sense), Yiddish and Luxembourgish. It refers to the upland and mountainous areas of central and southern Germany, it also includes Luxembourg, Austria, Liechtenstein and most of Switzerland. This is opposed to Low German, which is spoken on the lowlands and along the flat sea coasts of the north. High German in this broader sense can be subdivided into Upper German (Oberdeutsch, this includes the Austrian and Swiss German dialects), Central German (Mitteldeutsch, this includes Luxembourgish, which is now a standardized language), and High Franconian which is a transitional dialect between the two.