I've just begun the first edit of my longest novel, The Book Of Pain.
At a little over five hundred pages it's long for me at least and took quite a while to write. Yet by about page two hundred of the first edit, I've found something startling. My hero, as I recalled it, was forced to learn two languages in his quest to return home to England. The first was Latin, this being in the sixteenth century and all; and the second was portuguese. Yet on my first re-reading, that language has somehow, and strangely turned into spanish.
I just don't know how that happened. Admittedly I could only write a few pages per day and that was on my tablet at work before emailing it to myself then cutting and pasting it into the whole, so I didn't retain an overall view of the novel. I still can't, as much as I'd like to, spend the whole day at home writing, but it's taught me a lesson, and that is to take notes, or at least to re-read the earlier stuff as I write.
I'll fix it and everything will be well but I'm amazed at how I could let something so significant slip through, and wonder how many more mistakes I'll encounter along the way.