All languages studied in this project are spoken in the Indonesian part of New Guinea. Administratively, this area belongs to Papua, the easternmost province of the Republic of Indonesia, including the following districts (kabupaten): Paniai, Puncak Jaya, Tolikara, Jayawijaya, Yalimo, Yahukimo, and Pegunungan Bintang.

Most of the languages (e.g. Eipo, Yale, Yali) are spoken in the rugged high mountain range running across the island with the highest summits reaching 5000m. The landscape is characterized by narrow ridges and steep valleys, often crossed by small streams, rivers, and waterfalls. The villages and hamlets of the respective speech communities are usually located on top of the mountain ridges. On the steep mountainsides people lay out gardens, where sweet potatoes, taro, and other vegetables are cultivated. Other languages communities (like e.g. Wano) are found in the lowlands located on either the northern or the southern edges of the main mountain range, going down as far as 500m above sea level.