There are two contrastive phonemic tones in Telefol, high and low. For example, ùlín 'club' vs. úlìn 'planted'.
/e/ and /eː/, /o/ and /oː/, are nearly in complementary distribution. Also, single /e/ and /o/ don't occur in one-syllable words or in terminal syllables.
Vowel length only contrasts in initial syllables. However, in initial syllables single /u/ and /o/, and /i/ and /e/, don't contrast.
Telefol has a rich aspectual system.[7] Telefol verbs have "punctiliar" (momentary/completed) and "continuative" stems.[8]
Counting system
Telefol uses a base-27 counting system. This is mapped onto the body by counting each of the following: the left pinky to the left thumb (1-5); the wrist, lower arm, elbow, upper arm, and shoulder (6-10); the side of the neck, ear, and left eye (11-13); the nose (14); and similarly on the right side in reverse order, from the right eye to the right pinky (15-27).[9][10]
Kinship
Telefol has dyadic kinship terms (terms referring to the relationship two or more people have to each other), which are uncommon in the world's languages and not prevalent in Papua New Guinea. However, they are a salient feature of the Ok languages. Related terms are found in Oksapmin, Mian, and Tifal.[11]
^Laycock, Donald (1975). "Observations on Number Systems and Semantics". In Wurm, Stephen (ed.). New Guinea Area Languages and Language Study, I: Papuan Languages and the New Guinea Linguistic Scene. Pacific Linguistics C-38. Canberra: Research School of Pacific Studies, Australian National University. p. 223.
^Pawley, Andrew (2012). Hammarström, Harald; van den Heuvel, Wilco (eds.). "How reconstructable is proto Trans New Guinea? Problems, progress, prospects". History, Contact and Classification of Papuan Languages (Language & Linguistics in Melanesia Special Issue 2012: Part I). Port Moresby, Papua New Guinea: Linguistic Society of Papua New Guinea: 88–164. hdl:1885/38602. ISSN0023-1959.
Healey, Alan (1974). "A problem of Telefol verb classification". In Loving, Richard (ed.). Studies in languages of the Ok family. Workpapers in Papua New Guinea Languages. Vol. 7. Ukarumpa: Summer Institute of Linguistics. pp. 167–175.
Healey, Alan (1964). Telefol phonology. Pacific Linguistics, Series B. Vol. 3. Canberra: Australian National University. doi:10.15144/PL-B3.