Grypsera (Polish pronunciation: [ɡrɨˈpsɛra]; from Low German Gripps meaning "intelligence", "cleverness") is a distinct nonstandard dialect of the Polish language, used traditionally by recidivist prison inmates. It evolved in the 19th century in the areas of the Russian partition. Phonetically, Grypsera is similar to the Warsaw dialect and shares its most notable features of assimilation of ⟨i⟩ [i] into ⟨y⟩ [ɨ] and the disappearance of nasal vowels, especially in word-final syllables.