Two things have happened since my last post.
First, defiantly true is one of my favorite cupertinos, because very little can be defiantly true, unless it can be defiant, and at the same time, true. One poor woman in the writing lab had written it three times, and they were all in sentences such as That was defiantly a hard time for me, sentences in which it would be impossible for a time to be defiant, although it could of course be a hard time.
But this is what I figured out. Somebody claimed that you could adjust the Word grammar-check software to catch more contextual errors, cupertinos, times in which you needed there and wrote their for example. I didn't believe them, but I went looking for it, deep in the bowels of a Microsoft Word grammar-check at the computer station where I was working. What I found was a list of "change-to" words - such that any time you wrote cutsomer, it would change it to customer. They were clearly sensitive to words like that because they were trying to please the business world; if they had their finger on the pulse of the ESL world, they would have changed costumer to customer but in fact costumer is a word and that's why Word allows ESL students to get away with it.
Well in any event they added definately to this list and had it changed to definitely, and that's what accounts for the lower percentage of defiantly cupertinos that we are seeing these days. To American students, the biggest hazard was putting a single a in the word at the wrong time; but, the common error was fixed at some point, within Word. What remains are the other versions of the word, which cannot be interpreted as easily on the part of the computer, and thus remain in cupertino-land.
My poor American student either had an old version of Word, or, was typing something less typical. In any case, like most, she settled for defiantly, because it looked OK.