Tausūg is spoken by about 1 million people in parts of the
Philippines, in Malaysia, and in Indonesia, particularly on the Sulu
Archipelago, the Zamboanga Peninsula, Southern Palawan in the
Philippines, in Sabah in Malaysia, and in Kalimantan in Indonesia.
Tausūg a member of the Visayan branch of Central Philippine
languages, which is part of Malayo-Polynesian language family.
Tausūg is closely related to the Butuanon language of
northeastern Mindanao.
These days Tausūg is written with the Latin alphabet. From the
7th century it was written with a version of the Arabic alphabet
based on the Malaysian Jawi script. Tausūg was also written with
a version of the Baybayin script known as Luntar Sug from the 7th
century until the 16th century.
Tausug is primarily spoken in the Sulu Archipelago, which aside
from the island of Sulu, also includes the Tawi-Tawi chain of
islands and the island of Basilan. It is a lingua franca spoken in
different areas/islands of the archipelago.
Due to migration, the language is also spoken alongside other
local languages in the Zamboanga Peninsula (e.g., Cebuano and
Chavacano), which includes the provinces of Zamboanga del
Norte, Zamboanga Sibugay and Zamboanga del Sur and
Zamboanga City. It is also spoken in Southern Palawan and in
Eastern Sabah, Malaysia.
Sources: Wikipedia
https://omniglot.com/writing/tausug.htm