"I know. They even put steamed milk in it." The statement was a joke. A dry, self-deprecating joke, but a joke none the less. He'd learned what a latte was, but they hadn't been popular in the United States in the forties. Best to prepare poor Jean for the whole string of missed references and polite huhs? she was likely to endure.
The amused eye-twinkle was supposed to say 'joke.' Steve didn't realize that he probably should have been less subtle.
"Do you want anything? The woman at the counter said they had iced drinks as well as hot."