This is new territory, and perhaps someone else has more detail from any canon description of how {jal} gives Klingon the irrealis — the ability to talk about something that hasn’t happened and is likely never going to happen — can speak with more authority than I can. We used the language for a couple decades without this, and to be honest, I don’t see your average Klingon using this construction very many times in his life.
It's fairly simple. the net jalchugh clause sets up a
condition, and the rest of the sentence is the irrealis contingent
on that condition. The irrealis is not indicated morphologically
in Klingon. jImIp net jalchugh, puH Duj chu' vIje' If I
were rich, I would buy a new car. The Klingon sentence
literally means if one imagine that I am rich, I buy a new
car. The irrealis comes strictly from the idea that someone
is just envisioning something. The Klingon irrealis of this kind
is in the indicative mood. There is no grammatical subjunctive
mood in Klingon.
Without clarification from Okrand, just working from my experience with the language, {vaj} logically puts me in the world being imagined, but {ghIq} doesn’t give me that logical link back into the imagined world. It’s just a time stamp for the next clause.
I don't see vaj as necessarily implying something
hypothetical. HIchwIj vIpeppu'. vaj muHIvpu' jagh. I
raised my pistol. So the enemy attacked me.
Even with {vaj}, I wince a little, because it tempts me toward stringing together two Sentence As Object constructions, which is never a good thing. {jImIp net jalchugh vaj vIghro’ tIQ vIje’ net jalnIS, je.}
Okrand has decreed that net jalchugh is how Klingons form
this kind of irrealis, so your sentence is not required. jImIp
net jalchugh vIghro' tIQ vIje' is all you need to
express the concept of what I would do. This is one of
those Okrand-said-it-so-it's-true things.
In any case, I really think that you would better describe your fantasy of being rich and buying an ancient cat with {mIp’a’wIj vIjalDI’ reH vIghro’ tIQ vIje’ta’bogh vIjal je.} "When I imagine my great wealth, I always also imagine the ancient cat I bought.”
Except this is not how Okrand describes the irrealis construction
required. He doesn't say it can't have its variations, but you're
going out of your way to move mayqel's conforming use to a
non-conforming one.
It doesn’t even require an irrealis, since you imagine the wealth and you imagine the cat. These are real imaginings. The forthrightness and clarity feel natural for the language.
That's not what irrealis means. The hypothetical part of the
sentence is the buying of the ancient cat, not the existence of
the cat or the wealth. The existence of these other things is not
commented upon in the sentence.
What you want is an irrealis equivalent of the way time stamps work in Klingon. “Tomorrow, I go visit my cousin. We go shopping. We buy coffee. We sit and chat. I go home.” All that happens “tomorrow”.
You want to say, “I imagine that I am wealthy”, and you want that context of an imagined Universe that has a wealthy you in it to be the context that holds for a later statement. I’m not sure that Klingon can do that.
That is exactly what net jalchugh does. jImIp net
jalchugh, lorwI' vISuch, 'aH wIje', qa'vIn wIje', maba' 'ej
majaw, ghIq juH vIchegh. If I were wealthy, I
would visit my cousin, we would buy stuff, we would buy coffee,
we would sit and chat, and then I would go home. All of that
only happens in my fantasy of "if I were rich."
-- SuStel http://trimboli.name