The Defense Language Institute, located on the Presidio of Monterey, in downtown Monterey, California, is the primary language school of the Department of Defense, for instruction of DOD personnel in a variety of languages. Courses typically range from 25-63 weeks, depending on the difficulty of the language.

At The Defense Language Institute, they teach a variety of languages such as Russian, Serbian, Croatian, Chinese, Japanese, Persian Farsi, Dari, Arabic, French, Spanish, German, Korean. The biggest schools at DLI are Arabic and Korean. This is the biggest installation that Army, Navy, Marines, and Air Force all train together.