This is something I think I've noticed, but maybe I've just been noticing odd word choices and putting it down to a shift in language use. Has anyone noticed a shift from people using verb-derived nouns ending in -nce, to their equivalents ending in -ncy? Seems to be an American English thing.
For example, I've just read a scientific paper from a Washington-based research group, in which they use the word "resiliency", rather than "resilience". I'm sure I've noticed other words like this from time to time, but can't think of any more examples.