apu nikamut. She does not sing.
auen nekamut? Who sings?

When the verb nikamu is made an interrogative (who sings?), the conjunct form nikamut changes to nekamut. The first vowel changes from i (short i) to e.

The changed form of a verb results in a phonological change that affects the vowel of the first syllable in a verb or preverb. It can serve to create entirely new conjugations (like 12b and 14b).

The initial vowel change follows fixed rules, as illustrated below:

Rule Dictionary Form Unchanged Conjunct Form(e/ka/eka/apu + …) Changed Form
short i > e itu itin etin
short a > e atusseu atusset etusset
u > ue kushpu kushpiht kueshpiht
long i > a (not ia) pitutsheu pitutshet patutshet
long a > ia akushu akushiani iakushiani
e > ie metueu metuenanut mietuenanut
ei > iei peikupishu peikupishit pieikupishit
ai > ei aimu aimit eimit

Verbs with a long u act differently depending on the dialect. In the Eastern dialect, the changed form is iu, while in the other dialects the verb is preceded by e. The common spelling uses the latter form, as illustrated below:

Rule Dictionary Form Unchanged Conjunct Form Changed Form
long u > e + C + u pushu pushit epushit

For examples of changed form conjugations, see 11b, 12b, and 14b in the conjugation guide.