While in earlier classifications, Wolio, Laiyolo,[1] and later also Wotu,[2] were included in the Muna–Buton subgroup,[3] Donohue (2004) has shown that based on phonological evidence, the Wotu–Wolio languages form a distinct subgroup of their own.[4]
Mead (2003) included the Wotu–Wolio languages as one out of six branches in the Celebic subgroup.[5]
Zobel (2020) lists the Wotu–Wolio languages, which he calls Southern Kaili–Wolio, as Ledo, Wotu,
Wolio, Kamaru, Kalao, and Loa' (Barang-Barang). Wolio, Kamaru, Kalao, and Loa' (Barang-Barang) make up the Island Kaili–Wolio subgroup within Southern Kaili–Wolio. Ledo has Kaili–Pamona morphological and grammatical features, while its lexicon is mainly of Wotu–Wolio origin. Mamuju is traditionally classified as South Sulawesi, but has a Wotu–Wolio lexical substratum.[6]
^Noorduyn, J. (1991). "The Languages of Sulawesi". In H. Steinhauer (ed.). Papers in Austronesian linguistics. Pacific Linguistics A-81. Canberra: Australian National University.
^Donohue, Mark (2004). "The pretenders to the Muna-Buton group". In John Bowden; Nikolaus Himmelmann (eds.). Papers in Austronesian subgrouping and dialectology. Pacific Linguistics 563. Canberra: Australian National University. pp. 21–35. doi:10.15144/PL-563.21.
^Mead, David. (2003). "Evidence for a Celebic supergroup." In Lynch, John (ed.). Issues in Austronesian historical phonology, pp. 115-141. Canberra: Australian National University. (Pacific Linguistics 550)
Mead, David; Smith, Joanna. "The voice systems of Wotu, Barang-barang and Wolio: Synchronic and diachronic perspectives". In Malcolm D. Ross; I Wayan Arka (eds.). Language Change in Austronesian languages: papers from 12-ICAL, Volume 3. Asia-Pacific linguistics 018 / Studies on Austronesian languages 004. pp. 51–78. hdl:1885/13386.