Turku Arabic or simply just Turku is an extinct variant of Bimbashi Arabic that served as a lingua franca in Chad.
[1] It's the ancestor to Bongor Arabic[2] and potentially other Arabic pidgins spoken in Chad today, but since they have not been described, it is unclear whether they are direct descendants of Turku.
[3] Turku emerged as a regional variant of Bimbashi Arabic when Bimbashi-speaking enslaved soldiers were forced to relocate from Sudan to Chad after the abolition of slavery in Anglo-Egyptian Sudan in 1979.
[2] The primary lexifier of Turku is Sudanese Arabic, and it is also heavily influenced by Sango and Sara-Bagirmi languages, from which most of its loanwords originate.
Similar particles are also found in Juba Arabic and Nubi.