Khmer is the native language of the Khmer people and the official language of Cambodia, about 13 million people, with over one million speakers in Thailand and another million in Vietnam. It is widely spoken as the second language of various minority groups in Cambodia, including the Cham. Khmer is regularly taught at UW-Madison during the summers, at the Southeast Asian Studies Summer Institute, and through distance learning during the academic year through a program with the University of California-Berkeley. Cambodia has been open for travel, research, and social, religious, and economic engagement since the mid-1990s, with a large population of Cambodian Americans living in the United States since the late 1970s.