Rotwelsch

Rotwelsch (, "beggar's foreign (language)") or Gaunersprache (, "crook's language", also Kochemer Loshn (from Yiddish "חוכמער לשון", "tongue of the wise") is a secret language, a cant or thieves' argot, spoken by groups (primarily marginalized groups) in southern Germany and Switzerland. The language is based primarily on German.
During the 19th and 20th century, Rotwelsch was the object of linguistic repression, with systematic investigation by the German police.
Origin and development.
"Rotwelsch" was formerly common among travelling craftspeople and vagrants. The language is built on a strong substratum of German, but contains numerous words from other languages, notably from various German dialects, including Yiddish, as well as from Romany languages, notably Sintitikes. "Rotwelsch" has also played a great role in the development of the Yeniche language. In form and development it closely parallels the commercial speech ("shopkeeper language") of German-speaking regions.
Current status.
Variants of Rotwelsch, sometimes toned down, can still be heard among travelling craftspeople and funfair showpeople as well as among vagrants and beggars. Also, in some southwestern and western locales in Germany, where travelling peoples were settled, many Rotwelsch terms have entered the vocabulary of the vernacular, for instance in the municipalities of Schillingsfürst and Schopfloch.
A few Rotwelsch words have entered the colloquial language, for example, "aufmucken", "Bau", and "berappen". "Baldowern" or "ausbaldowern" is very common in the Berlin dialect; "Bombe" is still used in German prison jargon. "Bock haben" is also still used all around Germany. The Manisch dialect of the German city of Gießen is still used, although it was only spoken fluently by approximately 700-750 people in 1976.
Code.
Josef Ludwig Blum from Lützenhardt (Black Forest) wrote from war prison:
"[E]s grüßt Dich nun recht herzlich Dein Mann, viele Grüße an Schofel und Bock. Also nochmals viel Glück auf ein baldiges Wiedersehen in der schönen Heimat. Viele Grüße an Mutter u. Geschwister sowie an die Deinen."
The censors allowed the passage to remain, apparently believing that Bock and Schofel were people. They were instead code words, "Schofel" ("bad") and "Bock" ("hunger"), which hid the message that the prisoners weren't doing well, and that they were starving.
In arts.
A variant of Rotwelsch was spoken by some American criminal groups in the 1930s and the 1940s, and harpist Zeena Parkins' 1996 album "Mouth=Maul=Betrayer" made use of spoken Rotwelsch texts.
An example of Rotwelsch is found in Gustav Meyrink's "Der Golem" and reads as follows:
<poem>An Beindel von Eisen recht alt.
An Stranzen net gar a so kalt.
Messinung, a' Räucherl und Rohn,
und immerrr nurr putzen.
Und stoken sich Aufzug und Pfiff,
und schmallern an eisernes G'süff.
Juch,
Und Handschuhkren, Harom net san.</poem>