Think back, if you will, to the climactic scenes of Indiana Jones and the Last Crusade, which take place in the hidden temple that contains the Holy Grail. His father having been shot by the dastardly Nazi-sympathizing immortality-seeker Walter Donovan, Indy has no choice but to retrieve the legendary cup to make use of its reputed healing powers. This entails passing through three deadly chambers, one of which has a floor covered in stones, each one labeled with a letter of the alphabet. The way through, according to Jones père’s research, is the name of God. But when Indy steps on “J” for Jehovah, it crumbles away, and he nearly plunges into the enormous pit below.

Of course, true fans will have already quoted the relevant line: “But in the Latin alphabet, Jehova begins with an I!” Those of us who first watched the movie as kids — and, for that matter, many of us who first watched it as adults — simply took that fact as given. But if we watch the RobWords video above, we can learn how and when that “I” became a “J”.

Based in Seoul, Colin Marshall writes and broadcasts on cities, language, and culture. His projects include the Substack newsletter Books on Cities and the book The Stateless City: a Walk through 21st-Century Los Angeles. Follow him on Twitter at @colinmarshall or on Facebook.