>>18155915 (OP)
>>18155973 and
>>18156958 are somewhat correct..
Sudan was originally inhabited by Nilotic and Cushitic speaking peoples that got Arabized to various extents some completely speaking Arabic as their primary language. This happened after the fall of Christian Nubia, causing a mass exodus of Nilotic populations into South Sudan after various Arab tribes migrated and began to assimilate the Native population and enslave some Nilotic populations.
The Afro-Arabs of Sudan are completely Arabized, speaking only Sudanese Arabic, others within Sudan like Nilo-Saharan groups became Arabized but not fully like the Masalit, Nubians, and the Fur who kept speaking Nilo-saharan or Chadian dialects of Arabic, or the Beja who speak a Cushitic language. This wasn't good enough for the Afro-Arabs who took power after Egypt let go of Sudan in the 1950s after it got conquered in the 1800s. They started even heavier Islamization campaigns with the goal of making a Sharia state which exploded into heavy ethnic tensions causing the Christian Nilotic south to succeed and the less Arabized tribes of the West to be oppressed. It's an absolute shitshow.