Are children still taught to spell? Or how to use a dictionary?
Since the 1960s, it has been assumed by many teachers and parents that if children hear the correct pronunciation and read the correct spelling of words often enough, they will automatically speak and spell correctly.
My experience, both as a teacher, and as as a learner, have shown me very clearly that this so-called natural method, just does not work.
Those linguists that thought it would, overlooked the fact that for the first five or six years of our lives, we are continually corrected for slips in our first language.
Second languages are subjected to corrections in the school-room, but not when you are using them in the "real" world, as it is considered impolite to correct an adult or even a teenager. Bilingual children are corrected in both their languagues, but , there too, this process tends to stop when a child is about twelve.
I suspect that the tendency to confuse similar words is due to spelling not having been considered important.