Oh my gosh. I love this question. It made me feel all warm inside. I am just going to write about what immediately came to my mind and impressed me as true, even if it is not the whole story and some people who deserve credit get left out of the picture.
The answer is: my parents. The other part of the answer is: ...and more was caught than taught. I have simply grown up around good writing all my life. Now, hold the phone!!! This does not mean that I am saying that I am a good writer. It only means that I have always read and been exposed to competent writing. Like classical music and Protestant theology, it has been in my milieu since the cradle. Also, by my parents I do not mean their writing (although that is very much a part of the story), but the writing of the writers that they surrounded themselves with. I grew up with Tolkien and C.S. Lewis; with Lloyd Alexander and Kenneth Grahame; Shel Silverstein and Dr. Seuss; Shakespeare and T.S. Elliott. My mother read to me and my brother before we could read, and after we could read. We were taken to plays, watched PBS, and were taught to love literature and the fine arts. Again, though...not so much taught as taken along for the ride, because our parents loved it all so much and could not stay away from the things they thought were beautiful.
Then there is also my parents' writing. This, actually, is the very first thing that I thought of when I read this question. As far as my memory stretches back, I can see my father hunched over a paper, slogging over his own words and thoughts in addition to others'. Preparing papers for his Philosophy Club meetings (don't be a hater, now, Doc Rogers...ha!), writing up biblical commentaries and summaries (for no one to read...just storing them away for some time when someone might need it or take interest), and proofing, correcting, and discussing my mother's (constant) writing was what I always saw him doing, and it was a frequent topic of conversation between the two of them. My brother and I always heard these conversations, and sometimes we would participate in them. My mother cannot be imagined in the mind's eye without seeing her surrounded by books. I cannot separate her from her deep investment and associations with writing and language, in general. Books in Swahili, Kikuyu, French, and English (all of her languages); writers from the Caribbean, from countries in Africa, France, and her deep love and affection for those great Brits were just things that I never DIDN'T see. My father is a physics professor, yet he always found time to write about (and re-write about, proof, and beautify) his own ideas or to crack open Plato or William Blake to consult them. My mother, however, being a French and literature professor, was constantly spending deep time in writers and her own writing. It was literature, literature, literature, and language, language, language for her always.
When it came time for me to start writing formally in school, my father would go over my papers. From a very early age and all through high school (and, when we both had time, in the post high school years), he would mark up my papers in red and then we would talk about them. Even with all this, however, writing always came fairly easily to me. Again, I am not saying that I was good, or am good. I still could struggle mightily, and often could not even start. Oftentimes, my father had a lot to say about what I had written...LOTS to say. Through him, I had to learn, early on, how to fall out of love with my own errors and bad habits--as beautiful as they were to my young mind--and submit to making sense, being clear, and thinking writing THROUGH. No one has taught me more about writing, via conversation, than him. Via exposure and practice, nobody has taught me more about writing or instilled more love in me for writing than both of my parents together, who talked, dreamt, read, and wrote it all my life, right before my eyes. Much was caught daily, and from time to time--with a kind of deeply serious sense of pleasure on their part--a little was taught, in a big way.
