Polarization has changed the way that members of Congress vote. But it turns out it may also be changing the way they talk.

Congress now speaks at a 10.6 grade level — a high-school student, halfway through sophomore year — down from a 11.5 grade level in 2005, according to a Sunlight Foundation analysis of the Congressional record.

Generally speaking, the most moderate members on both sides of the aisle speak at the highest grade levels, whereas the most politically extreme members speak at the lowest grade levels. Before 2005, Republicans had spoken at a higher grade level than Democrats; now it’s flipped. Newer members are also likely to speak more simply than more senior ones, so freshmen Republicans are most likely to speak at the lowest grade level in Congress.

(Sunlight Foundation)

The Sunlight Foundation calculated the grade levels using readability tests that measure the number of words per sentence and the number of syllables per word. As such, the grade levels aren’t a pure gauge of intelligence: a legislator could score lower by being more plainspoken and, perhaps, accessible to the general public, By comparison, most major newspapers are at a 11-14 grade level, and most Americans read at a 8-9 grade level. Obama’s last State of the Union was at an 8th grade level, below the 10.7 average for the last 67 addresses.