Republicans and Democrats aren’t just polarized on policy. To an unprecedented degree, they also speak different languages.

That is the conclusion of three economists who used computers to parse 136 years of transcripts of congressional speeches. They identified phrases used disproportionately by members of one party or the other, and tested the degree to which use of those “partisan phrases” accurately predicted the affiliation of a member of Congress — in other words, the degree to which Republicans and Democrats effectively have a language of their own. They found that language polarization skyrocketed in the mid-1990s, when Newt Gingrich and Bob Dole led Republican majorities in both chambers of Congress.

In the Congress from 1873 to 1874, armed with only the text of a one-minute speech on the floor of Congress, you would have had a 54 percent chance of guessing the speaker’s political party. By the session from 1989 to 1990, that had edged up only to 55 percent. In the 110th Congress, which ended in early 2009, that had risen to 83 percent, according to the new working paper by Matthew Gentzkow, Jesse M. Shapiro and Matt Taddy.

Using congressional vote records, political scientists have identified something of a “U” shape to political polarization in the United States: It was very high in the late 19th century and start of the 20th, before receding during the middle of the 20th century and surging higher in the last generation.