All grades for postgraduate students are based on their writing. In the United States, MA theses are not required for all programs. Even formal writing is not emphasized, students usually take two exams and write one paper in a course. This means that they write nine to twelve papers, excluding an MA thesis, which are usually more informal and shorter than the papers students in a British university write. Another important part of the linguistics program here is research groups.
Most teachers have a research group on a particular topic that has periodic meetings.
Students can join them if they wish. I think most MPhil and PhD students, and many MA students, are members of one or more groups. Some groups have reading and discussion sessions. Some have a kind of lecture series, which each member makes a presentation. Some work on projects together.