I was thinking about your comment about your “discovery that apparently I have no fixed pronunciation for the words ‘aunt’ and ‘route'” and I had to laugh. Because those words (not to mention “envelope”) vary for me, too. And because how many of us readers have had the experience of knowing words but not knowing how they are pronounced?
But there’s also the whole issue of pronouncing especially foreign words and place names when you are reading aloud. I remember that when I read Lloyd Alexander’s Prydain books aloud, I always pronounced Fflewddur Fflam something like “Flewthur Flam.” A few years ago, I listened to The Book of Three on audio, and the reader pronounced it more like it looks: “Flewder Flam.” At the time I wondered where I had gotten the idea to pronounce it as I had, although I was certain that I had read it somewhere.
Then last year, after Susan Cooper was named the Margaret Edwards Award winner by YALSA, I re-read the whole “Dark is Rising” sequence, and realized that that was where I had read that in Welsh, the “dd” is pronounced as a “th.” (And this could lead us to a whole other discussion about the things we have learned from books that came in handy in other parts of our lives!)
The question of pronunciation came up again during the whole Harry Potter craze. I read the books, but also listened to all of Jim Dale’s narrations of them, so I had definite ideas about how various words and names should be pronounced. I don’t know if you remember, but shortly before the seventh book came out, Hank Green (on what was then Brotherhood 2.o) wrote and performed the song “Accio Deathly Hallows.” In the song, Hank pronounces “accio” as “axeo.” Jim Dale pronounced it “AH-seo” and other commenters thought it should be more like “AK-eo.” And so on. But I had Jim Dale’s voice so firmly implanted in my head that I was certain he must be right.
Although, oddly enough, even Jim Dale changed some pronunciations during the course of reading the seven books. In the first couple, he pronounced Voldemort as if it were a French word, dropping the final “t” sound (like Stephen Colbert!). But in the later books, he made it sound more English, with a firm final “t.”
I think I’m pretty good at reading aloud and pronouncing words correctly, but you will have to tell me, as you read more and more chapter books to your own kids, if you come across words that you remember hearing differently as a child than the way you would now pronounce them. (Of course, I might have let some midwesternisms slip in at times, too–hard as I tried to get rid of any trace of Kansas in my voice!)