These steep southern slopes are nearly uninhabited, thus an effective buffer between languages and culture in the Terai and Hilly. Paharis mainly populate river and stream bottoms that enable rice cultivation and are warm enough for winter/spring crops of wheat and potato. The increasingly urbanized Kathmandu and Pokhara valleys fall within the Hill region. Newars are an indigenous ethnic group with their own Tibeto-Burman language. The Newar were originally indigenous to the Kathmandu valley but have spread into Pokhara and other towns alongside urbanized Pahari.