By trivialities, I was referring to single keywords. It's the originality, arrangement of the words, the similarity of the expression as a whole that forms the test for 'copy' vs. 'derivative work' in copyright law. Google just copied, and they copied not just a list of common and widely used words in technology contexts. They could have made their own API with a similar set of functions and Oracle would have nothing to say, but they didn't. There are already dozens of APIs in different languages all providing the same essential services, but you don't get copyright lawsuits because they're different expressions of the same idea.
German dogs could be trained with a different set of words. But as I said, that's not the point, the copyright wouldn't be in the idea of training dogs, the command words, or even just the list of words, it would be in the training manual, which any number of people could write a version of, describing the same techniques, and still have copyright protection. You don't see the first person who wrote a "hammering nails for dummies" book start legal action against everyone else who describes carpentry techniques.
The dispute here is whether an API definition is just a list of words (no copyright) or the expression of an idea worthy of copyright protection. I think the latter, under current US law. So do the DoJ, apparently.