Timothy Usher, Santa Fe Institute
The Ramu River family is comprised of 22 to 25 languages spoken along and around the Ramu river and its tributaries in the Bogia and Middle Ramu subdistricts in the northwest portion of Papua New Guinea's Madang province and along and around the Keram and Porapora rivers, tributaries of the Sepik, in the far eastern postion of East Sepik province.
The internal classification of Ramu River is as follows:
Ramu River
Waran (Banaro)
South Ramu River
Rao
Aram-Aren
North Ramu River
Lower Ramu River
Ramu Coast
Ruboni Range
Central Ramu River
Porapora River
Guam and Moam Rivers
Guam River
Moam River
Z'graggen (1969, 1971: 89, supplemented with family- and stock-level figures from pp. 75-88) gives lexicostatistical relationships between selected languages of the Ramu Phylum as follows, with subgroups designated and ordered according to the current classification:
| Banaro | S. Ramu | S. Ramu | Ramu Coast | Ruboni | Moam R. | Guam R. | Porapora R. | ||
| Banaro | Rao | Aiome | Gamei | Mikarew | Tanguat | Breri | Adjora | ||
| Banaro | Banaro | — | 11 | 5 | 6 | 3 | 6 | 5 | 8 |
| S. Ramu | Rao | 11 | — | 10 | 6 | 8 | 8 | 5 | 8 |
| S. Ramu | Anor | 9 | 13 | 58 | 6 | 10 | 9 | ||
| S.Ramu | Aiome | 5 | 10 | — | 5 | 9 | 11 | ||
| Ramu Coast | Awar | 5 | 8 | 41 | 15 | 11 | |||
| Ramu Coast | Gamei | 6 | 6 | 5 | — | 12 | 14 | ||
| Ramu Coast | Kaian | 77 | 14 | 6 | 6 | ||||
| Ruboni R. | Mikarew | 3 | 8 | 12 | — | 12 | 9 | 14 | |
| Ruboni R. | Giri | 8 | 19 | 42 | |||||
| Moam R. | Andarum | 9 | 12 | 37 | 15 | ||||
| Moam R. | Tanguat | 6 | 8 | 9 | 12 | — | 20 | 8 | |
| Moam R. | Igom | 9 | 12 | 39 | 17 | ||||
| Moam R. | Tangu | 9 | 36 | 15 | |||||
| Guam R. | Akrukay | 8 | 9 | 23 | 38 | ||||
| Guam R. | Breri | 5 | 5 | 9 | 20 | — | 15 | ||
| Guam R. | Midsivin. | 6 | 13 | 12 | 42 | ||||
| Porapora R. | Adjora | 8 | 8 | 11 | 14 | 14 | 8 | 15 | — |
| Porapora R. | Gorovu | 5 | 51 |
(n.b. Z'graggen 1971: 89 gives both 14% and 18% between Mikarew and Adjora, we believe 18% to be a misprint.)
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Proto Guam River had perhaps 15 consonants and at least 4 vowels as follows:
| *m | *n | *ŋ | |
| *p | *t | *s | *k |
| *mb | *nd | [*ndz] | *ŋg |
| *w | *r | *j | *ɣ |
| *i | *ʉ | *u |
| *a |
Any consonant can occur medially.
Only a restricted set of consonants occurs initially:
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Only a restricted set of consonants occurs finally:
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| Ramu River | Banaro | Middle Ramu | Lower Ramu | Porapora | Guam-Moam |
| *… | |||||
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