I went to a community college, then a private liberal-arts oriented school, then grad school for computer science. In my community college writing courses, I was often the only student who turned in papers that met the requirements (for instance, being “research papers” rather than essays). At my four-year school, I had professors comment to me outside class that I was far and away the best writer in their courses and they were surprised I was a comp sci major (I always gave my mother credit for teaching me to write)
Now, in graduate school, those of us for whom English was a first language all seemed proficient at producing papers (usually, one research paper/project report per course). I’m not sure if that reflected the higher intellect required for grad school or what but my fellow CS students and I were certainly head and shoulders above my old undergraduate classmates for writing.
My mother, who has a high school education, taught me how to write a mean paper. She did it so well, I don’t have to think about it. Since I was homeschooled she knew it was part of her job but any parent could, with a few hours a week, teach writing skills to her child. If, that is, they know their kid needs help...
We have homeschooled our son since 7th grade and he is a very good writer as well. However, he and I are working on the research notations and other requirements this year.