Proto-Gäj language

Proto-Gäj (PGäj) is the reconstructed ancestor of the Nambāno and Arklobu languages, which together form the "Gäj" branch of the Arklobu-Qachkav languages.

Consonants
The voicing of the plain PAQ plosives *p *t *c *k → *b *d *ɟ *g is assumed to have already taken place in Proto-Gäj due to the reflection of PAQ *cʰ *c by Nambāno /s z/, which would be an unusual change without first going through the voicing step, as well as some additional evidence from Arklobu. The aspirated plosives *pʰ *tʰ *cʰ *kʰ may well have retained their aspiration, but the only contrastive feature which can be reconstructed for Proto-Gäj is the voicedness, so their reflexes are transcribed *p *t *c *k.

Phonological Development from Proto-Arklobu-Qachkav
The following sound changes are reconstructed to have occurred, roughly in the order presented, in the development of Proto-Gäj from its ancestor Proto-Arklobu-Qachkav. In each example given, the start (PAQ) and end point (PGäj) for each word is shown, with relevant intermediate steps underlined.

Transitive Verbs
Transitive verbs had three conjugation paradigms, perfective, imperfective and irrealis. Each conjugation has a set of suffixes which mark the person of the subject and a set of prefixes and infixes which mark TAM information and show agreement with the subject. Both sets of affixes distinguish first person singular and plural in all conjugations, while in the case of imperfective and irrealis conjugations with second or third person subjects, the person is marked by the suffix and the plurality is marked by the prefix/infix.

The suffixes, which determine the conjugation, are shown below. The perfective series is simply a continuation of the PAQ perfectives {*-ʡx₁əʡ, *-ʡx₃əkʰʊ, *-ʡx₃əkʰi, *-ʡx₁əʡx₃, *-ʡʊːpʰ, *-ʡʊːkʰ}, of which Proto-Gäj is in fact the primary source for reconstruction. The -(h)- is present only on vowel-final verb stems.

The imperfective suffixes appear to be descended from PAQ infinitive series {*-kʰi, *-kiː, *-kʰiːkʰ, *ʡiː} with an unknown suffix *-r. This unusual development represents the only finite verb forms developed from the PAQ infinitives present in the Arklobu-Qachkav family.

The irrealis suffixes are the reflexes of four of the six reconstructed suffixes in the PAQ conditional series {*-(ə)ntʰx₂əʡ, *-(ə)ntx₂əʡʊ, *-(ə)nqtx₂ə, *-(ə)ncʰʊːʡ, *-(ə)ntx₂əjʊ, *-(ə)nqtx₃əʡ}.