That's known as a "shibboleth", after a story in the Bible about the Ephraimites who pronounced the Hebrew "sh" as "s" and so were identified by (and slain for) saying "sibboleth" rather than "shibboleth":
> The Gileadites captured the fords of the Jordan leading to Ephraim, and whenever a survivor of Ephraim said, “Let me cross over,” the men of Gilead asked him, “Are you an Ephraimite?” If he replied, “No,” 6 they said, “All right, say ‘Shibboleth.’” If he said, “Sibboleth,” because he could not pronounce the word correctly, they seized him and killed him at the fords of the Jordan.
- Judges 12:5
In WW II, a well-known challenge/password/countersign set used by American and British soldiers during the D-Day landings in France was "flash"/"thunder"/"welcome". "Thunder" and "welcome", of course, are words that a German is likely to mangle.
This lives on today in the questionable origins of the brand name Lululemon:
> It was thought that a Japanese marketing firm would not try to create a North American sounding brand with the letter “L” because the sound does not exist in Japanese phonetics. By including an “L” in the name it was thought the Japanese consumer would find the name innately North American and authentic. Chip felt that the distributor had paid a premium for the “L” so he challenged himself to come up with a name that had 3 “L’s” for his new company.
so are Americans trying to say Eichhörnchen (the German word for squirrel). I’ve used that as an icebreaker for kids in a German-American exchange program - both groups trying to say the word in the other’s language.
I appreciate the thorough response. I experienced a variation on the thunder/flash challenge response when a group from work played night paintball after work one Friday night. The other team established a code: 'Pizza' was the challenge, and if the other person didn't answer 'Hut' they'd be splatted. I thought it was really clever and only learned about thunder/flash and shibboleths later.
> The Gileadites captured the fords of the Jordan leading to Ephraim, and whenever a survivor of Ephraim said, “Let me cross over,” the men of Gilead asked him, “Are you an Ephraimite?” If he replied, “No,” 6 they said, “All right, say ‘Shibboleth.’” If he said, “Sibboleth,” because he could not pronounce the word correctly, they seized him and killed him at the fords of the Jordan.
- Judges 12:5
In WW II, a well-known challenge/password/countersign set used by American and British soldiers during the D-Day landings in France was "flash"/"thunder"/"welcome". "Thunder" and "welcome", of course, are words that a German is likely to mangle.