- During World War II, some United States soldiers in the Pacific theater used the word lollapalooza as a shibboleth to challenge unidentified persons, on the premise that Japanese people often pronounce the letter L as R or confuse Rs with Ls. In Oliver Gramling's Free Men are Fighting: The Story of World War II (1942) the author notes that, in the war, Japanese spies would often approach checkpoints posing as American or Filipino military personnel. A shibboleth such as "lollapalooza" would be used by the sentry, who, if the first two syllables come back as rorra, would "open fire without waiting to hear the remainder".
- During the Allied breakout from the Normandy beachheads in 1944, hand-to-hand fighting occurred throughout the hedgerows and thick undergrowth of the Norman countryside. British and American troops were told to use the word "Thunderer" as a countersign through the thick foliage. Given the number of syllables and the leading "th" sound, it was believed that the word would invariably be mispronounced by native German speakers.
(MANY others on the linked page)
For those interested in the french definition + spelling :