There's probably a word I've been pronouncing wrong my whole life that I don't know about

https://discuss.tchncs.de/post/10066578

There's probably a word I've been pronouncing wrong my whole life that I don't know about - tchncs

A "niche" is not a "nitch"

You're a bit too late for trying to complain about that one.

The latter has been the dominant American pronunciation of the word for so long that it now appears as the primary pronunciation guide in American dictionaries.

Definition of NICHE

Definition of 'niche' by Merriam-Webster

I hope cache isn’t pronounced like cachet (rhymes with sashay) rather than cash.
It varies by region at least in the US based on a few years of doing service desk work. Listening to YouTubers, it seems a bit all over the place as well.
It likely correlates with French influence in the Sputh, seeing as it is a French word.
Some of the the Louisana folks would often say ka-SHAY in a wonderful Cajun accent.
They’re exactly the ones who should know better…