@WW When I teach academic IELTS and the two thousand must-have "academic" words, I wonder why we have and use them when for quite a few there are fairly straightforward Saxon words of the same-ish meaning. This is the nub of it.
Of course if one wishes to knowingly step outside the hidebound word-stock then and plough a new furrow so to speak, it does not of itself betoken disdain for the now-in-being collocations; just that there is a wealth of little-used older and dialect words which give us wider choices.
That being said looking at Latinate words with undersight and struggling to get round them is not always do-able; after all we are talking about a 5000-7000 word hole in everyday and academic word-stock. For instance we might use "hiree" instead of "employee", (hireling is to ill-deeming); "wageslip" for payslip; but "pay" and "payroll" are hard to bestead, so I think quite a few Norman/French words are best left to stand.

support -> also underpin, underbear

We might be actually better off actually getting rid of articles like "the" and "a/an" actually, as many languages actually do do without articles, as they sometimes don't actually add a lot of meaning, and some languages actually do do without them anyway, and anyway adverbs are actually much more fun.

Should that be "said the cast-member to the ecclesiastic" ??
Or perhaps is was a "personage a trois" ?? (a threesome)

In the beginning some people had fun with words like wo-people, person-ager, and disagree-people-t. Alas it's all frowned on now.

"If I had studied, I would have gotten a good grade." (but I didn't - it didn't happen)
“If I had studied, I would have a good grade.” (but I don't - ie present)

"Would" indicates a non-real idea (what looks like the past tense sometimes meaning it won't or didn't happen eg If I were rich..) ; "have gotten" indicates the past (a perfect infinitive if you will).

"uppityness " : to me "uppity" suggests someone is unbiddable, wayward, or unwilling to take overlordship. I see the meaning "snobby" in the wordbook but I've never heard it.
How about "one-upmanship"?

@Warsaw Will: dinosaurs like me lay eggs
Ruthfully my career in business ended b4 some spider spun the worldwide web: quite how an office really works with emails is beyond my ken, although sometimes I write php, html, or javascript just while away a sunny retirement.

@warsaw will: many "English" teachers in Korea (and elsewhere) are in fact American. So students learn "movie" not "film".
Now, are you going to insist on "Have you finished your homework?" (pres perf)
Again, we hear "we was" and "he were" every night on Coro Street.
Once upon a time in Eastern Europe I met girl (occupational hazard). She had a rich Manchester accent .... I never dreamt it masked her Czech origin.
Times have moved on and students need English for business and/or university, fast. Building up their word-stock is more useful than spending class time on the finer points of grammar, such as: "I am meeting her tomorrow" vs "I am going to meet her.." Nor should we forget that "continuous" forms are being well over-used by a quarter of a billion English speakers on the Indian subcontinent.
In short, RP is a quirky regional sub-dialect, why do you teach it? Why not English exactly like the Queen speaks?
I always wanted to say all this when training new teachers....just to stir them up...Of course it's OTT but who knows what all those new young Americans really say????
Fins ain't wot they used to be, guv.

@Warsaw Will : Not suggesting you are wrong; just we need some more concrete benchmarking. I think everyone has a dialect; yours may well be more "catholic" than some. It is all about the audience; whether the reader/listener understands correctly; (or if the examiner thinks it is okay).
"The government is" /"the government are" either makes no difference to the meaning.
However "the government" vs "government" may well make a difference; (and more of an issue for slav speakers.) At the end of the day it is only meaning that matters, not grammar of itself.

@Warsaw Will Just teach your student to always write the month in letters like "Mar" when putting dates in emails. And watch the use of a comma for the decimal point.
I think one of the early Mars probes crashed because of the feet/meters issue in the software.
"My boss's car was kaput so I gave him an elevator to the airport" !!
With hearty greetings.