It doesn’t attempt the kind of analysis I try with the State of the Union addresses, but chir.ag has a great visual tool that builds tag clouds for hundreds of important presidential speeches and texts, all the way back to the Declaration of Independence and George Washington’s State of the Union speeches.
The site has a slider, allowing you to dynamically scroll through the clouds, seeing at a glance what words stick out during what time periods. In the late sixties, “Vietnam” is very bold, indicating it was used quite frequently in presidential speeches. The word “economic” dominates the seventies.
Here’s one surprise: during the eight Reagan years one prominent word is “God.” And that’s one word that doesn’t often appear in G.W. Bush’s speeches, even though he is far more evangelical and beholden to the Christian Right than Reagan ever was.
One thing that would make chir.ag’s dynamic tag cloud even more functional would be an “anchor” feature, in which you could select a specific word, and that word would be highlighted all the way through the hundreds of clouds, whenever it appeared. It’d be fascinating to take an unlikely word (for example, “healing”–which was one of the top 100 words in Gerald Ford’s first address to Congress on August 12, 1974) and see who else uses that word and in what contexts.