In many cultures, the classroom teaching model is the expert delivering a steady stream of knowledge to students who do not ask questions. This tradition can seep into a didactic presentation style among tour guides. Americans like more give and take, Mr. Lennox said.

“We teach guides to ask what their group is interested in, and what they already know, so the tour can be customized,” he said. Guides are also taught to observe and respond to body language for signs of interest or disinterest.

Even compliments and expressions of gratitude can be tricky. On his tours in Guyana in South America, Mr. Lennox noted that some rural guides would give overweight Americans a thumbs-up and say things like, “Ah, packing it on — good deal!” as a compliment, equating an ample waistline with abundant wealth.

Conversely, Americans seemed to say “thank you” for everything the guides did, a custom that made the local people feel indebted to them, Mr. Lennox said.

Learning cultural cues is important for guides and tourists alike, given the large number of people from the United States who visit other countries. Tens of millions of Americans travel abroad each year, according to the Commerce Department. And when they travel, nearly 40 percent of American leisure travelers overseas participate in some kind of guided tour, according to the research website Statista.com.