The University of Tartu Institute of Foreign Languages and Cultures offers various language courses for beginners, intermediate and advanced learners. You can also participate in culture courses. Many of them are taught on the basis of Estonian, but a variety of courses are also taught on the basis of English. Pick the language you would like to learn and read more about the courses taking place this semester.
When you have found a suitable course, read more about registering. You can register for spring semester courses from December 16, and classes start in February. You can register for the autumn semester courses from May 15, and classes start in September. Courses usually last for 15-16 weeks, all course schedules are based on the university's academic calendar.