It's been an interesting election cycle for political language. The recent focus on the striking similarities between Michelle Obama's 2008 and Melania Trump's convention speeches led our group to wonder about the overall similarity of prospective and current FLOTUS speeches. Are they talking about similar or different things? Political pundits initially claimed that the passage was not plagiarized since spousal convention speeches tend to be very similar. (The speechwriter for Melania Trump finally admitted to lifting language from Michelle Obama's speech.)
We decided to tackle this claim empirically. Using the TASA LSA space to measure semantic similarity, we find that the overall content of Michelle Obama's and Melania Trump's speeches produces a similarity rating of 0.835, showing they are more similar than 88.6% of other spouses’ speeches. Interestingly, while candidates' spouses do generally tend to speak similarly, their words have more variation than do the presidential candidates'.
POTUS Language and Semantic Similarity
Thinking about semantic similarity among potential FLOTUS speeches also made us curious about the POTUS candidates’ speeches as well. We illustrate this with two heat maps; one shows similarity across party lines and one shows similarity within parties. Figure 1 illustrates that in most elections the Republican and Democratic candidates’ convention addresses are very similar. The two most dissimilar are 1984 Reagan-Mondale and 2016 Trump-Clinton.
The 1984 Reagan-Mondale election also represented a point of transition in the topics of debate between the parties. Much like the early 1980s, the relationships shown on these heat maps suggest that 2016 could indeed be a pivotal moment in defining a new political climate. Hilary Clinton’s address is clearly a natural continuation of Democratic candidates’ addresses in the post 1984 era while Trump’s Republican address represents a break with past.