The Middlebury Language Schools, starting with the establishment of the School of German in 1915, offer intensive undergraduate and graduate-level instruction in 10 languages during six-, seven-, or eight-week summer sessions. The Schools enroll about 1,350 students every summer. The Schools all use an immersion-based approach to language instruction and acquisition. All students in the Language Schools must sign and abide by Middlebury College's "Language Pledge", a pledge to use their target language exclusively during the duration of their time at the School.