Above is a graph from an interesting study on the changing use of language by congressfolk.
...[referring to] the 20 members of Congress with the lowest grade level score for their Congressional record corpus dating back to 1996. Of them, 85% (17 of 20) are Republicans; 65% (13/20) are freshmen, and another 15% (3/20) are sophomores. Additionally, 90% (18/20) are House members. The two Senators to make the bottom 20 are Rand Paul (R-KY) and Ron Johnson (R-WI), both Tea Party-supported freshmen.
Republicans also outnumber Democrats among the members who speak at the highest grade levels. Among the top 20, 12 are Republicans, 7 are Democrats, and one (Joe Lieberman) is an Independent. And eight of the top ten are Republicans. There are also 14 House members and six Senators. And perhaps most notably, there are only two freshmen and three sophomores. More than half of the members have been in their seat for at least 15 years, which is well above the median of nine years across all members of the 112th Congress.