Pronouns

The pronouns Ross reconstructs for proto-Tariku are,

I	*a/*i	we	*a/*ai
thou	*de	you	*da
s/he	*au	they	?

The corresponding "I" and "thou" pronouns are proto–East Lake Plain *a, *do, Awera yai, nai (the latter from *dai; compare also e "we"), and Rasawa e-, de-. Saponi shares no pronouns with the Lakes Plain family; indeed its pronouns mamire "I, we" and ba "thou" are remenincent of proto–East Bird's Head *meme "we" and *ba "thou". However, Saponi shares half its basic lexical vocabulary with Rasawa, and Ross left it in the Lakes Plain family pending further investigation. The Tause language was also previously grouped amongst the Tariku group of Lakes Plains languages. Ross transferred it to the East Bird's Head – Sentani languages on the basis of pronoun similarities; he hoped this would promote further research.

Phonology

Clouse and Clouse (1993) note many of the Lakes Plains languages share several unusual phonological features. While Papuan languages typically have at least two nasal phonemes, this is not the case for Lakes Plains languages. Although phonetic nasals do exist in most Lakes Plains languages, they do not contrast with the corresponding voiced stops. Doutai, Sikaritai and Obokuitai lack even phonetic nasals. Additionally, no Lakes Plains language has a liquid phoneme. Clouse (1997) reconstructs for the ancestor of Lakes Plains the typologically remarkable consonant inventory, consisting entirely of stops, /p, t, k, b, d/.

Many of the languages have very high constricted (fricativised) vowels; in Doutai and Kirikiri these constitute separate phonemes from /i/ and /u/. The fricativised vowels seem to have developed from deletion of a following consonant.