L1 users: 60,000 (2010 SIL), increasing.
Arua district: Madi-Okollo county; Yumbe, Nebbi, Zombo, and Nyadri districts.
Okollo, Ogoko, Rigbo. Reportedly more similar to Lugbara [lgg] than to Ma’di (Moyo) [mhi], which they do not understand. Ogoko and Rigbo dialects are more similar to Lugbara [lgg] than Okollo; intelligibility testing needed. Okollo considered most pure. Southern Ma’di dialects in Rigbo, Ogoko, and Okollo areas, should be considered Lugbara dialects (SIL 1992 Moru-Ma’di Survey Report). Lexical similarity: 85% between Ogoko dialect and Adjumani Ma’di [mhi], 83% between Okollo and Ogoko, 80% between Ogoko and Arua Lugbara, 80% between Ogoko and Moyo Ma’di, 78% between Ogoko and Moyo Ma’di, 76% between Okollo dialect and Arua Lugbara [lgg], 64% between Okollo and Moyo Ma’di, 59% between Okollo and Adjumani Ma’di [mhi] (Boone and Watson 1999).