"Trainings" dates back to at least 1811 in AmE, used in military. You can find it via Ngram
"Informations" on DW is sometimes heard from newsreader, reporter or interviewee.
"Accomodations" is widely used in AmE and I've gotten used to it.
NB "Akkomodation" in German (and French?) are usually false friends.

I do agree, in Europe (outside the UK) education is in some ways better, (along with public transport, double glazing, central heating, clearing the snow, plain speaking ...)

"And why shouldn't Standard English open up a bit, after all it isn't even the mother tongue of most British white children. It's a language we can all use in common, but is it so terrible if a few dialect expression creep in? "
Exactly. That's what I mean when I say we need a more catholic approach.

The question is where does one draw the line?
"Conversate" shows a steep rise in usage after 2000 (on Ngrams), so might be on the way to becoming "mainstream" (whatever that exactly means).
"Informations" in the plural does exist properly as legal jargon in criminal law in mainstream English. However it is commonly used by English-as-second-language speakers, where mainstream English would used an uncounted form without the 's'.
(happens a lot on Deutsche Welle).
If one googles "general informations" one can see that information is being pluralized in quite a number of contexts, and maybe that too is beginning to make its way into mainstream English.
The other thing that may not live on for ever is today's familiar tool-kit of idioms and collocations. I use them myself of course - "the sad fact is...." ; "sweeping changes", "great weather for ducks" - but that doesn't mean that we should downgrade someone who doesn't use the cliched word-string. Better to leave the door open to new input:
"Great weather for frogs" (as they say in Korean).

@HS You do write such beautifully-crafted English and I am sure it is nettling to see that others do not. We all seem to judge what is right and wrong by the standards of our youth, what we were taught at school and so on; but each new generation makes up its own mind, so there's no sense in getting in a pother about it. We too shall pass.

@WW It is not uncommon in Eastern Europe for multinationals to sweep in and require all management employees to learn English, or use English for all internal documentation, both for their own benefit and also so their own auditors have access to documents. There is little alternative for people who wish to find / keep a good job.
I was just wondering how you yourself would feel if you had to file your lesson plans in Polish to keep your job. Less than enthusiastic?

To be clear, I was simply trying to point out that for many people English is a second language, not their native tongue, and that in the future this may well impact on what is today regarded as "standard" English.

@HS Frankly, a far, far bigger issue is that there are notable areas of England where English is no longer the number one language, and over three hundred primary schools where not one of the children has English as their first langugage.
Who knows, one day soon the Gorbals might be Chinese-speaking or something.
Where I live, half my neighbours have limited or no English, and three out of four local supermarkets don't even have any signage in English; whether they speak any, I know not. All the other shops, doctors, pharmacy, restaurants, and so on have English as a second language, apart from The Post Office which is still holding out, making a last stand.
Beneath it all, even "Standard English" is going to come under pressure to become more catholic. Perhaps the only bulwark against sweeping change is the spell-checker, and the fact that some scripts like Chinese require multi-byte storage on computers not ASCII.

"Wake up, Colonel-sahib, we were losing the sepoys in 1947."

The mechanism is already there; it's called a spell-checker (checks grammar too).

"Ok guys, listen up: there's nothing wrong with your own language, just it's NBG if you want to get ahead"...

@WW How enthusiastic would you be about having English forced on you if your own language was, say, Polish or Gujurati?

en.wiktionary.org/wiki/conversate
en.wikipedia.org/wiki/African_American_Vernacular_English

Apparently "conversate" is a dialect word, normal in AAVE, which also has its own grammar.

Converse? What that mean, yo?

@WW "I teach in large and small corporations" - in my day that meant waiting in the snow for the tram at 0630, first class in-company at 0730, another tram.. and so on till mid-evening. I wish we'd had "Email English" (Macmillan) then but it was all too new. Whenever I duck into a coffee shop nowadays, it all comes back. Is this you too?

"leverage" is AmE term for BrE "gearing", although I've not heard the latter in a long time now in this sense. in, say, renting out property, the higher the mortgage, the higher the gearing or leverage; and the higher the risk if it all turns to custard. However property is usually a safe bet so high leveraging is acceptable to the lender; the same would not be true of an untried start-up. In accounting and finance AmE terminology has taken over, under the sway of the IASB (International Accounting Standards Board).

@Brus I thought in this case your logic was very logical.
The first hurdle in teaching English (to non-English-speakers) is to decide what is English - usually American or British, but in fact the devil is in the detail. Even if we go for "standard" English, this is not the end of the story.
In real life people need to be able to understand a variety of spoken English and dialects in order to do business, or attend university, or work on a global help desk, or work in a factory in Glasgow, or sell water management systems to the Pakistani Government or whatever. (And as obiter dictum, I might add that for some reason Welsh accents aren't in the textbooks, but Spanish, Chinese, Japanese, and German accents are).
But when it comes to spelling (which in English is little guide to pronunciation) some standardization does help communication, and with spell-checkers is now very easy.
When I started teaching I thought I knew English and what was right and wrong. Well I did. But it was my English, from my miieu, from my part of the English-speaking world. I now know better. Even the following, which sounds "wrong" to me, is apparently okay in Quebec:
"If I would win the lottery, I would buy a Mercedes".
This means one has to be quite catholic in one's approach, and sometimes check dictionaries to find out about how English is used outside one's own experience. There is also the issue of change over one's lifetime - particularly true when it comes to opening and closing business letters and emails, where what is commonplace now would have been out of place forty years ago. Again, it is a question of de facto usage rather than one's own ideas.