At the turn of the twentieth century, the Sedoa language was spoken in two locations: in the upland Tawaelia river valley (>1000 m elevation) just north (upstream) from the Napu valley, and in the lowlands near the mouth of the Tambarana River on the Gulf of Tomini (Adriani 1898:554). In the present day, however, the language has remained preserved only in the upland location, that is, in the village of Sedoa.
Although Sedoa borders the Napu language area, since at least Adriani and Esser (1939:vii–viii) it has been recognized that Sedoa shares its closest linguistic affinities with Lindu and Moma across mountain ranges to its west.
Susan Shore (2010:pers.comm.) reports 900 speakers in Sedoa village. When the road linking Palu with Napu was completed in 1982, it ran through the Tawaelia valley and opened this previously isolated location to greater immigration (for an overview of immigration to the Napu valley, see Abdulkadir-Sunito 2004:92–94). The village of Sedoa is now home to not only the native Sedoa people but also a sizeable Bugis population (Hanna 2004:2).
Although an additional three thousand ethnic Sedoa live outside of the Tawaelia valley, they mostly do not speak the language (Susan Shore:2010:pers.comm.).
Abdulkadir-Sunito, Melani. 2004. Orang kampong and pendatang: Analysis of demographic structure and migration in two forest-margin villages, Central Sulawesi. Land use, nature conservation and the stability of rainforest margins in Southeast Asia, edited by Gerhard Gerold, Michael Fremerey and Edi Guhardja, 89–104. Berlin: Springer.
Adriani, N. 1898. Overzicht over de talen van Midden-Celebes. Mededeelingen van wege het Nederlandsche Zendelinggenootschap 42:536–586.
Adriani, N.; and S. J. Esser. 1939. Koelawische Taalstudiën, part 1: Overzicht der spraakkunst, gesprekken en verhalen met vertaling. Bandoeng: Nix.
Hanna, Roger. 2004. An introduction to the grammar of Napu. Unpublished typescript.