Discourse in the House and Senate has dropped a full grade level — to the equivalent of high school sophomore, according to a new study. Call this the dumbing down of Congress in a partisan age. Or a shift to plain-spoken populism ignited by the new class of tea party Republicans. But what has become clear in the new research is that the soaring oratory that once filled the floors of the House and Senate with million-dollar diction and sophisticated syntax is making way for a more modest approach. "Congress is changing as an institution, and what you see is more and more members gearing their speeches as sound bites or YouTube clips," said Lee Drutman, a senior fellow at the nonpartisan Sunlight Foundation, which compiled the study released Monday.