Ah, you’re not alone for suffering angst when you hear certain usages, Kevin. I think we all hear things that set our teeth on edge. But it’s why a descriptive (rather than prescriptive) approach is so important in linguistics. Languages change and we have to chart those changes.

So glad you liked the video Efrossini and well done for spotting the different spellings of moustache in British and American English. You might be interested to hear that We use the word in the singular these days. I know some dictionaries still list it as a plural word (it was in the 19th century) but it’s singular in modern English. Thanks so much for writing and your kind comment. Much appreciated.