Grypsera

Grypsera (; from Low German "Gripps" meaning "intelligence", "cleverness") is a distinct nonstandard dialect or slang of the Polish language, used traditionally by recidivist prison inmates.
It evolved in the 19th century in the areas of Congress Poland and the Warsaw prison that is colloquially called Gęsiówka is said to be where it originated. The basic substrate of the dialect is Polish, but there are many notable influences (mostly lexical) from other languages used in Polish lands at that time, most notably Yiddish and German, but also some Lithuanian, Ukrainian, Russian, Greek and Latin. It was also heavily influenced by various regional dialects of the Polish language, most notably the Bałak jargon of Lwów and the Warsaw dialect.
Initially, it served the role of a cant, or "secret language", but in the late 19th century, it became a standard sociolect of criminals. Grypsera is constantly evolving to maintain the status of a language understood only by a select group of inmates and not by the wardens or informers. That makes it currently one of the lexically richest dialects of Polish. Also, it is not possible to prepare a comprehensive dictionary of the dialect since it differs from prison to prison.
Phonetically, Grypsera is similar to the Warsaw dialect and shares its most notable features of assimilation of into and the disappearance of nasal vowels, especially in word-final syllables.