I have no idea why Americans pronounce the word differently but there is no conspiracy and both are accepted in their respective areas of the world.

Part of the reason neesh doesn’t sound correct to me is that nitch actually sounds like what it is. When I think of nitch, i think of a small opening in a surface, like a crevice in a stone wall that a little creature lives in. The creature specializes in inhabiting that space, and there’s no room for others. That’s a pretty good definition of niche (nitch). Neesh, on the other hand, doesn’t sound like anything in particular–just vaguely French.

Here’s what I think happened: everybody in America always said nitch until one day, somewhere in the 1990s, someone in broadcasting saw it written for the first time and decided that, since it looked French, they’d sound smarter/cooler if they gave it a French pronunciation. everyone who heard him/her do this on the air did a quick mental nitch/neesh comparison and, even though everyone grew up hearing it nitch, many figured hey, the radio guy must be smarter than me since he speaks French, so it must be neesh. Huh! Who knew?

Therefore, without any discussion whatsoever, millions of Americans simultaneously ON THE SAME DAY decided that the word niche was pronounced neesh instead of the way they had always heard it. I know this will sound far-fetched to many of you, but that’s the way ideas travel in this day and age. It’s the same as an urban legend, a persistent myth. For example, I have been told by several very well-educated people that the Daddy Long-legs is actually one of the most venomous creatures there is, but it’s fangs are too small to penetrate our skin, so we’d never know it. This claim is false. There is no evidence behind it whatsoever, regardless of how you interpret it. Yet I’m sure it won’t go away, for the same reason that I’m sure I’ll continue to hear people say neesh: people believe that propagating it makes them sound smarter.

I hearby challenge anyone out there listening to find me a recording of an American saying neesh from before, say, 1990. I bet you can’t because I bet they didn’t.