Understanding <iv>

[Kisora]

I need help to understand the infix <iv>. I have tried hard to see how it works and so far, have still failed. Taronyu's extended inflections with more uses of <iv> have not helped too..
My English is fine but I yet cannot understand some linguistic terms.

Let's start with the basics, what's subjunctive?

[tìngay mungeyu]

Kaltxì,

In grammar, the subjunctive is a verb mood typically used in dependent clauses to express wishes, commands, emotion, possibility, judgment, opinion, necessity, or statements that are contrary to fact at present. It is hard to explain what the funcion of the subjunctive is but I found quite a long explanation on Wikipedia or you can check these threads:
http://forum.learnnavi.org/intermediate/subjunctive-moods/msg68843/?topicseen#msg68843
http://forum.learnnavi.org/intermediate/ltivgt/
http://forum.learnnavi.org/prefixes-infixes-and-suffixes/subjunctive-aspect/