I've been reading the writings of average people lately, and have come to some conclusions about grammar.
- Many people struggle with the distinctions between "lie" and "lay". At times, I hesitate about the correct usage. But, if I experience difficulty, I have a sufficiently large vocabulary that I can re-state my words to avoid use of a questionable phrase. Most people do not, and are forced to make a guess (the fact that such guesses are so often wrong should be a strong indication that the proper use is counter-intuitive).
- One major reason that everyday grammar is so often wrong is that people base their usage on the spoken word. Dialect is more common now than 40 years ago, a situation that I wouldn't have anticipated. I thought that with the prevalence of television, people would become aware of the correct phrasing, and substitute it for the speech they had learnt from their birth family.
That hasn't happened. TV has "dumbed down", and most shows feature non-standard English.
- One way people used to become familiar with Standard English was in reading. By the time my grandparents left school, they had developed a habit of reading, and had absorbed the rythyms of Standard English into their internal dialogue. Today, few read, even in school. Most homes have few books.