One of the more important tools used by programmers is the so-called diff tool. “Diff” stands for difference, and the tool is used to spot the differences between similar versions of the same program. This problem comes up more often than you might think, especially when two or more people are messing around with the same group of files. Here’s an example.
Typically the text on the left is considered the original file and the text on the right is considered the modified file. Lines with white backgrounds on both sides are identical. New or modified material in the right side gets a green background. Old or removed material on the left side gets red. All this helps your eye spot the changed areas. As you can see, someone has taken some serious poetic license with this rhyme.
This tool that was invented for programmers can be used with things other than programming code. It can dissect variants in a poem, as above. Or it can be used to visualize the evolution of a speech.
Last night Bill Clinton gave a 49 minute speech at the Democratic National Convention. That’s a short speech compared to the stem-winders of yesteryear, but long by modern standards. And not only that, he terrified his handlers by departing from his prepared text for long stretches. How far off? Software to the rescue! Here’s a nice piece in the Atlantic that spells it out for you, using the same kind of diff tool I describe above.
In the judgment of many listeners, his ad libs improved the speech considerably. My favorite insertion: I’m fixing to tell you why. I reckon that little feller wasn’t in the prepared text. Say what you will about his politics, but that boy got a big ol’ head on him to keep all them little words up there.