FWIW, I thought that “cachet” meant “a stash of stuff”. So maybe that’s part of the confusion. I am familiar with “cache” (pronounced “cash”) from both the military and computer worlds. I’m not sure what I thought that the difference in “cache” and “cachet” were. I never really thought about it.
Literally, “hide pot”, and I would pronounce it as “cash poh”, as the “t” isn’t pronounced in French.
FWIW, I’d pronounce “cachet” more like “cash-eh” than “cash-ay”, which just sounds very exaggerated to me. The latter is closer to my pronunciation of the past participle of “to hide”, caché, but even then the accented e isn’t nearly as stressed as the “ay” sound usually is by non-francophone speakers. Perhaps writing it as “cash-ei” would be better… the é is more like the sound in “weigh” than it is like the sound in “say”.
It depends on the dialect. I guess I say “cachet” in a similar way to you ([kaʃɛ], basically, in the International Phonetic Alphabet), while I pronounce “caché” [kaʃe], but in some French dialects – I think it’s the case of Parisian dialects, for example – the last vowel in these two words tends to sound the same. In any case, you’re correct that the ‘é’ vowel doesn’t really sound like ‘ay’ anyway.
I think it’s pretty common in military usage. In fact I have never heard it mispronounced by anyone other than military. There is no point in trying to correct it, there’s a sense of mulish pride involved now.
I wonder if it is useful, because even though it is mispronounced, it is not similar to any other word in common usage in a military context? There are a couple other words like that, they escape me right at the moment. Damnit, now that is going to bug me.