Timothy Usher, Santa Fe Institute
The Mongi River family consists of at least two closely-related languages, Dedua and Kube-Tobo, spoken south of the Cromwell range from the Kua river valley in the west to beyond the Mongi river as far east as the headwaters of the Masaweng in Papua New Guinea's Morobe province. Its nearest linguistic relatives are the Bulum River languages to the southwest (McElhanon 1967: 5-6, Suter 2018: 6, q.v. p. 4.)
The internal classification of Mongi River is as follows:
Mongi River
Dedua
North Dedua
South Dedua
Kube-Tobo
Tobo
Kube
Kurungtufu
Yoanggeng
According to Lee (1993: 10,) Tobo is a dialect of Kube with 95% cognacy over nearly 200 basic terms, much higher than McElhanon's (1967: 6-9) figure of 71.4% (below.) Thus a conservative tally would count only two rather than three languages in the Mongi River family.
McElhanon (1967: 6-9) gives lexicostatistical figures between Dedua, Hube (Kube) and Tobo as follows:
| Dedua | Hube | Tobo | |
| Dedua | — | 50.7 | 42.9 |
| Hube | 50.7 | — | 71.4 |
| Tobo | 42.9 | 71.4 | — |
We assume Dedua's figures to have been significantly depressed by loans from Kâte, which are pervasive enough to have moved Hooley and McElhanon (1970 :1069, 1070) to reclassify Dedua in the East Huon family (below.)
Pilhofer (1927-1928) comparative morphology for Dedua and Kube
Pilhofer (1928-1929) 290 comparative terms for Dedaue (Dedua) and Hube (Kube)
McElhanon (1967: 34-43) 140 comparative terms for Dedua, Hube (Kube) and Tobo
McElhanon (1968) 1,495 comparative terms for Dedua, Kube-Yoangen, and Tobo
McElhanon and Voorhoeve (1970) 67 Trans New Guinea comparisons include examples from Tobo, Kube and Dedua
McElhanon (2012) 2,020 comparative terms for Tobo and Yoangen Kube
Smith (1988) Morobe counting systems (unobtained)
Ceder and Ceder (1988) grammar of Dedua (unobtained)
Ceder and Ceder (1989) dictionary of Dedua (unobtained)
Ceder and Ceder (1990) grammar of Dedua (unobtained)
Ceder and Ceder (1990) orthography of Dedua (unobtained)
Ceder and Ceder (2003) sketch phonology of Dedua
Ceder and Ceder (n.d.) dialect survey of Dedua (unobtained)…
Lee (1993) grammar of Kube
Lee (n.d.) dictionary of Mongi (unobtained)
Gasaway (1997) Burum morphophomenics
Blake (2000) Dedua participants
Blake (2000) Dedua clitics (unobtained)
Mankins (2012) grammar of Tobo (unobtained)
Mankins (n.d.) dictionary of Tobo (unobtained)
Suter (2018) comparative Pindiu grammar including (pp. 43-51) Pindiu object-marking verbs and (pp. 182-188) Pindiu desinences
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Proto-Mongi River had … consonants and … vowels as follows:
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…
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… initial consonants …
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| Mongi River | Dedua | Dedua | Kube | Kube | Tobo | Tobo |
| McElhanon | Ceder | McElhanon | Lee | McElhanon | Mankins | |
| *… | ||||||
| *… |
… medial consonants …
…
| Mongi River | Dedua | Dedua | Kube | Kube | Tobo | Tobo |
| McElhanon | Ceder | McElhanon | Lee | McElhanon | Mankins | |
| *… | ||||||
| *… |
… final consonants …
…
| Mongi River | Dedua | Dedua | Kube | Kube | Tobo | Tobo |
| McElhanon | Ceder | McElhanon | Lee | McElhanon | Mankins | |
| *… | ||||||
| *… |
… vowels and diphthongs …
…
| Mongi River | Dedua | Dedua | Kube | Kube | Tobo | Tobo |
| McElhanon | Ceder | McElhanon | Lee | McElhanon | Mankins | |
| *… | ||||||
| *… |
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