Occasionally, I tell Amy what things are called in American English.
I usually couch it in terms of "Ben says 'X'", due to some English-for-children DVDs that she has with two anthropomorphic animals called Ben and Bella, wherein Bella speaks [a native German's approximation to] British English, while Ben speaks [ditto] American English. So she's already noticed that they occasionally pronounce things differently, and sometimes I point out how they might also use different words (e.g. sidewalk, flashlight).
Hopefully, she won't be as confused as I was the first time I came across the word "faucet". (Which reminds me, that's a word I haven't told her about yet. They're all "taps" here.)