Members of Congress leave the Capital after the House went on recess for Thanksgiving.

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he language employed by members of Congress in their public speeches has fallen a whole grade level in the last seven years, according to a new study. Using the Flesch-Kincaid test, which assigns higher grade levels for the use of longer words and more complex sentences, the Sunlight Foundation concluded that the average lawmaker speaks at a 10th grade level, down from the 11th grade level in 2005, but still two or three grades higher than the typical American. Why do our elected leaders sound like high school sophomores? Here, three explanations:

1. Extremism makes lawmakers sound stupid
"Polarization has changed the way that members of Congress vote," says Suzy Khimm at The Washington Post. And "it may also be changing the way they talk." Moderate politicians typically speak at the highest grade levels, while those at the extremes speak at the lowest. And "newer members are also likely to speak more simply than more senior ones." Just a few years ago, Republicans sounded smarter than Democrats. But as the GOP has veered to the far right, Congress has been flooded by insurgent freshman Republicans who rank near the bottom of the linguistic scale, dragging down the class average.

2. Politicians are just getting more concise
"We do it on purpose," freshman Rep. Mike Mulvaney (R-S.C.), who ranked lowest with a 7.9 grade level, tells CNN. "People have been teaching this for decades. If you want someone to understand your message, you speak clearly and concisely." Ernest Hemingway wrote simple sentences, but that doesn't mean he was less mentally acute than William Faulkner, who employed more complex language. "I don't think anyone equates the polysyllabic nature of your words [with] intellect," says Mulvaney, who graduated with honors from Georgetown University and earned a law degree at the University of North Carolina, Chapel Hill.

3. Congress isn't dumb. This study is.
Our lawmakers don't talk like 10th graders, says David Haglund at Slate. The Flesch-Kincaid test is "an enormously reductive little tool" that was meant to measure precision of language, not smarts. People misuse it to impugn politicians they dislike. In January, Republicans guffawed over reports that President Obama's State of the Union speech was assessed at an eighth grade level, a new low for modern presidents. Now liberal journalists are trumpeting the Sunlight Foundation's findings because it gives them license to call Congress' new Tea Party contingent "sophomoric." Enough is enough.