The Department of Computer Science offers different master's degree programs, each with its own admissions criteria and degree requirements. Thus, although you may be in courses with other CS graduate (and undergraduate) students, the following requirements are only for the CL MS degree, and not for the other MS programs in Computer Science.
The Two-Year CL MS degree requires four semesters of enrollment for full-time students, and full-time GSAS students must take a minimum of three courses per semester. Thus, a minimum of 12 courses are required for all Two-Year CL MS students, whether full-time or part-time.
Fifth Year BS/MS students must complete the same 12-course requirement to complete the CL MS, but will have taken some of these courses during their undergraduate studies. Since the MS year for BS/MS students requires two semesters of enrollment for full-time students, this means that a minimum of six courses must be taken during this fifth MS year.
There are four basic types of courses that will make up the 12 minimum courses taken by each CL MS student.
For full-time students, four semesters of enrollment are required for the Two-Year CL MS, and two semesters for the Fifth Year CL MS. After the required number of terms of residency are completed, full-time students who need to enroll for one or more additional semesters (e.g., to complete remaining course requirements or the exit requirement) have an 'Extended Master's' enrollment status. This means that they are still allowed to enroll in courses just as an ordinary full-time student would, but pay substantially less in tuition fee amounts.
There is no residency requirement for part-time students. Instead, the counterpart for part-time students involves completing the 12 courses minimum (along with all courses required for the degree) that corresponds to full-time students' minimum of four semesters of residency at three minimum courses per term.
In order to complete the CL MS degree, students are required to complete a CL MS thesis (via the course COSI 299a - Computational Linguistics Master's thesis) or a CL internship at a company (via the course COSI 293b - Computational Linguistics Research Internship). As mentioned above, each of these counts as a regular course toward full-time enrollment (thus carrying the full four credits that ordinary courses have), and toward the minimum 12 courses needed to complete the degree.
The Exit Requirement is typically done in the final semester in the program. With the permission of CL advising faculty, students can opt for either of these to span two semesters rather than one, and/or to complete both a thesis and an internship.