I would say, by informal survey, that most literary translators (and reporters, who seem to delight in the phrase), present it in transliterated Arabic: insha’allah.
After all, English-language readers “know” what it means (or think they do), and it gives a flavor (not too spicy!) that they’re expecting. Those Arabs, they just love their God.
I had noted earlier that Ahdaf Soueif says she is “very careful” about using Arabic terms in her English-language texts.
Mehrez added:
And the religious formulas are a case in point. How important is it for a Western reader to have a formula like insha’allah stand in the text as insha’allah, when it doesn’t mean God willing—it really doesn’t mean that when people say that. They mean a million other things.
The same could be said for “el hamdul’allah” and other oft-heard phrases that invoke a diety. Further, Mehrez says:
Obviously that’s constantly misread…that these are a religious people, that they cannot speak one single sentence without a religious evocation.
And indeed: I am not a religious person, but I use these phrases constantly. Once, I was out having coffee with a friend who uses these phrases exceedingly rarely. I told her that I would be home by four o’clock, insha’allah. She turned to me—because she is also this sort of friend—and said, “What do you mean by that?”
For a moment, I was speechless. Finally I said, Well, traffic on Gezirit Suez looked bad going the other direction, and maybe I’ll be stuck, and…and….
So on the one hand, I had meant something akin to the English “I hope”: Traffic looked bad, I hope I’ll get home by 4. But on the other hand, it was also an acknowledgment that getting home by four o’clock was not something entirely under my control. I wanted to be home by four; I’d promised to be home by four; but would I be?
So what is a translator supposed to do?
a) Leave it in the text as insha’allah, potentially exoticizing the work, re-creating the (expected) hyper-religious Arab?
b) Translate it as “God willing” or “I hope” or “we’ll see,” depending on the context?
c) Erase it from the text entirely?
None of these seem a particularly satisfactory answer. I would love it if someone else had a d), e), f), or g)….