When I studied English at school I had an interesting time of it. I generally got on well with the teachers, got excellent marks for my in-class work, and, unlike the vast majority of my peers, had no trouble with classics like Shakespeare.
Then I failed the O-grade English exam everyone sits at 16. I was baffled. My teachers were baffled. They wrote it off as an anomaly and filed an appeal against my result using my classwork and the preliminary exam I'd taken earlier. I was also assured that even if I did not get the appeal, I would be allowed to study for and sit the Higher exam.
I did just that, and got an excellent grade in the Higher exam. My teachers were disappointed that I chose not to study English further, but I was much more interested in my science and mathematics courses.
It was when I had my first job in IT that I discovered that my "excellent English" was lacking in a number of respects. My first boss was an old ex-IBM guy who'd been in in the industry since punched cards were commonplace. My repeated casual faults were knocked out of me, and for specifications and proposals I learned to be far more concise.
Nowadays I am used to seeing screeds of specifications that make far, far worse mistakes than I used to. The worst ones are those that come from India. Senior management look at the lengthy buzzword-compliant nonsense and seem to think, "good, we saved lots of money." I just shake my head. You can tell a mile away which projects will be a complete failure - because it is painfully apparent in the specifications who understands the actual requirements, or more accurately who doesn't.
I saw a consumer TV piece that really brought this home to me. The reporter asked a number of professors to provide sample assignments they would generally use with undergraduates. These questions were then submitted to a number of websites that offer to have Indian graduates write the paper for you. Every single returned paper was given a failing mark by the professors.
English may be an official language in India, but in so many cases they just write to meet certain criteria with a grammar check using Microsoft Office.