It encompasses the dialects of cities such as Aachen, Bingen, Bonn, Cologne, Duisburg, Düsseldorf, Eschweiler and Eschweiler, Essen, Eupen, Gennep, Gummersbach, Heinsberg, Karlsruhe, Kaiserslautern, Kerkrade and Herzogenrath, 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 Rheinische Dokumenta uses the letters of today's ISO basic Latin alphabet, without ⟨c⟩, ⟨q⟩, ⟨x⟩, ⟨y⟩, ⟨z⟩, though it has the digraphs ⟨ch⟩, ⟨c͜h⟩, ⟨ng⟩, trigraph ⟨sch⟩.
These ambiguities are avoided writing Rheinische Dokumenta; despite the fact that word stems may change their printed appearance, when declined or conjugated, always the most phonetically correct letters, digraphs, or trigraphs are being used.
There are diacritics to indicate them, but since they are seen to considerably hamper readability, make prints ugly, and are hardly necessary to facilitate understanding, they are seldom used.
For the other ones, there are only a very few word pairs or triplets having identical unaccented Rheinische Dokumenta spellings but different tonal or stress accents.
There are 14 short vowels in the languages that the script was designed for, 13 of which are representable in Rheinische Dokumenta: The "e̩" is [ə], a schwa.
Glottal stops are not noted in Rheinische Dokumenta, even though they are phonemes occasionally having minimal pairs and a length attribute.
Since this schwa almost always corresponds to the digraph "er" ending a word or a separable syllable prefix of Standard German orthography, most users of Rheinische Dokumenta positionally print "er", or "e̩r", respectively, for increased readability in an attempt of courtesy towards their readers who read German more fluently than Rheinische Dokumenta.
There are occasions, when two monophthongs need to be written together without forming a diphthong; that means they are pronounced separately with either a glottal stop or an intervocalic joiner consonant "j" in between.
The number of diphthongs existing in a dialect is far less than each possible combination of two vowels, thus there are not very many ambiguities when taking syllable structure into account.
If, for instance, Rheinische Dokumenta was used in writing Westphalian, triphthongs would be written in a manner analogous to the diphthongs, using three adjacent letters of vocals.
Since most dialects follow the German, and Lower Franconian, rule of final-obstruent devoicing, voiced consonants cannot, or hardly ever, appear at the end of a word or sentence.
Though some dialects vary the duration of nasal consonants considerably, they are not doubled to indicate extended length when written, while vocals are.
A good argument against doubling is that often nasal durations depend on speaker, style of speech, and prosody rather than being a characteristic of a word or a dialect, although that is not always so.
Few West- and Central Ripuarian languages, most notably Colognian, have the non-allophones [ʃ] and [ɧ][4] Both are written sch in Rheinische Dokumenta.
Most Rheinische Dokumenta prints choose it to be slightly more angular, longer, and thus appear bolder than ogoneks usually are.
The phoneme denoted by ŋ in print, alternately spelt ng, never appears at the beginning of a syllable, word, or sentence.