Have you replaced any British words with their American versions?
For example, switching out the word 'boot' for 'trunk', or ditching the word 'rubbish' for 'garbage'.
This is something I've noticed my 6 year old does pretty regularly. We went through a stage where 'sweets' became 'candy', 'holiday' became 'vacation' and 'courgette' became 'zucchini'.
That last one didn't happen but if you're still reading you've got my respect, or as the Americans might say '...mad props'.
I seem to use movie when describing the blockbuster/B-movie end of the scale, and film when talking about a quality bit of cinema. But I also am more likely to call a US flick a movie and a Brit one a film.
I like the sound of the word autumn, and particularly autumnal. I can see those reds and browns and feel the crisp air. Fall does give more opportunity for puns and easier rhymes, I guess.