Sudanese Arabic, also referred to as the Sudanese dialect (, ), Colloquial Sudanese ( ) or locally as Common Sudanese ( ) refers to the various related varieties of Arabic spoken in Sudan as well as parts of Egypt, Eritrea, Ethiopia, and Chad. Sudanese Arabic has also influenced a number of Arabic-based pidgins and creoles, including Juba Arabic, widely used in South Sudan, as well as Ki-Nubi, spoken by the Nubi communities of Kenya and Uganda. Sudanese Arabic is highly diverse. Famed Sudanese linguist Awn ash-Sharif Gasim noted that "it is difficult to speak of a 'Sudanese colloquial language' in general, simply because there is not a single dialect used simultaneously in all the regions where Arabic is the mother tongue. Every region, and almost every tribe, has its own brand of Arabic." However, Gasim broadly distinguishes between the varieties spoken by sedentary groups along the Nile (such as the Ja'aliyyin) and pastoralist groups (such as the Baggara groups of west Sudan). The most widely-spoken variety of Sudanese is variably referred to as Central Sudanese Arabic, Central Urban Sudanese Arabic, or Khartoum Arabic, which more closely resembles varieties spoken by sedentary groups. Some, like researcher Stefano Manfredi, refer to this variety as "Sudanese Standard Arabic" due to the variety's comparative prestige and widespread use. Linguist Ibrahim Adam Ishaq identifies two varieties of Arabic spoken in Darfur besides Sudanese Standard Arabic, including Pastoral Arabic and what is generally termed Darfur Arabic, which refers to the Arabic primarily spoken by multilingual Darfuris living in rural parts of the region. A number of especially distinct tribal varieties, such as the Arabic spoken by the Shaigiya and Shukriyya tribes, have also elicited special interest from linguists. The variety evolved from the varieties of Arabic brought by Arabs who migrated to the region after the signing of the Treaty of Baqt, a 7th-century treaty between the Muslim rulers of Egypt and the Nubian kingdom of Makuria. Testimonies by travelers to the areas that would become modern-day Sudan, like Ibn Battuta, indicate that Arabic coexisted alongside indigenous Sudanese languages, with multilingualism in Arabic and non-Arabic Sudanese languages being well-attested by travelers to the region up until the 19th-century. Accordingly, linguists have identified a variety of Nubian, Beja, Fur, Nilotic, and other influences from Sudanese languages on the vocabulary and phonology of Sudanese Arabic. By the 16th and 17th centuries, the Sultanates of Darfur and Sennar emerged