The Rheinische Dokumenta is a phonetic writing system developed in the early 1980s by a working group of academics, linguists, local language experts, and local language speakers of the Rhineland. It was presented to the public in 1986 by the Landschaftsverband Rheinland. It offers a uniform common notation of almost every phoneme spoken in the Lower Rhine area, the western and central Rhineland, the Berg region, the Westerwald, Eifel, and Hunsrück mountain regions, plus the areas surrounding the Nahe and Moselle Rivers. It encompasses the dialects of cities such as Aachen, Bingen, Bonn, Cologne, Duisburg, Düsseldorf, Eschweiler, Eschweiler, Essen, Eupen, Gennep, Gummersbach, Heinsberg, Karlsruhe, Kaiserslautern, Kerkrade, Cleves, Koblenz, Limburg, Ludwigshafen, Luxembourg, Maastricht, Mainz, Malmedy, Mönchengladbach, Nijmegen, Oberhausen, Prüm, Raeren, Saarbrücken, Siegen, Trier, Venlo, St. Vith, Wiesbaden, Wipperfürth, Wuppertal, Xanten, and many more.
Rheinische Dokumenta was designed to be easily readable for dialect speakers educated in German writing, but there are some differences that make it quite distinct from the usual ways of writing the dialects: There is no doubling of consonants to mark short vowels, and there are extra diacritical marks. The German letters ⟨z⟩ and ⟨x⟩ are spelled ⟨ts⟩ and ⟨ks⟩, German ⟨ch⟩ is spelled ⟨k⟩ when it indicates a /k/ pronunciation, German ⟨qu⟩ is spelled ⟨kw⟩. These spellings appear in other Germanic languages as well, but Rhinelanders are generally not accustomed to them.