May I know when this group was established?
Hello. I learned in a text that we can say 'May I know...?' in formal situations. But an American teacher of English told me it sounded unnatural. He said 'May I borrow your phone?' is okay (but formal). He said he has never heard any native speaker use 'May I know...?'
But I found these examples on this website: https://ell.stackexchange.com/search?q="may+I+know"+
And these examples on Reverso: https://context.reverso.net/перевод/английский-русский/may+i+know
May I know if this American teacher was correct? He says May + to know sounds weird because we don't need to ask permission to know something.
Note: I ask about normal English contexts, not about contexts like a servant talking to master!
He says things like "Could you please tell me...? and "Would you mind letting me know...? are much more natural. Are there other ways?
Also, is there a difference between British English? Is 'May I know...?' more natural in British?
He also said to look at this Google gram: https://books.google.com/ngrams/graph?content=May+I+know&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2CMay%20I%20know%3B%2Cc0
May I know what this gram means?