I'd be very surprised if some grammar wasn't taught at all. Formal writing in the UK would be in an absolute state of disarray if this were true. The US teache

I'd be very surprised if some grammar wasn't taught at all. Formal writing in the UK would be in an absolute state of disarray if this were true. The US teaches most terms. It's pretty important to know what prepositions are, and how adjectives and adverbs differ. Lots of more complex topics do come up, but kids don't listen. It's not immediately applicable to their life so it goes in one ear and out the other. Plenty of people say also schools need to teach how to balance a checkbook and teach some basic finance. They do--but kids aren't paying attention, because no 5th grader should be out there balancing checkbooks for quite a few years, and no kid really cares what a "preposition" is either until they're learning another language or trying to improve their writing and suddenly need to dig back into those memory banks. But people who say to not study grammar usually don't make progress. What's worse is some people say "don't worry. Our language has no grammar." Every language has some basic rules to learn. The problem is some textbooks heavily front load some formal grammar because a lot of adult learning materials are focused on business usage, and they come with the implication that somehow a person is going to go from zero to handling diplomatic meetings in a month. Japanese textbooks are notoriously bad for emphasizing very formal speech (sometimes even excessively formal speech) before delving into more casual stuff that people will use 90% of the time. Then you meet a person and the grammar you've studied doesn't align with most of what's immediately practical, and it's easy to conclude it "doesn't matter".