Xishuangbanna (often just Banna is used; Chinese: 西双版纳; Lü: ᧑᧒ ᦗᧃ ᦓᦱ) is in the south of Yunnan, near the Thai, Laotian, Vietnamese and Burmese borders. The ethnic groups and the local languages in this area are more Southeast Asian than Chinese.
The region is a very popular destination for Chinese tourists. It offers most of the attractions of Thailand — warm climate, tropical fruits and flowers, elephants, prostitutes (legal in Thailand, illegal in China), jungle treks and a reasonably well-established tourist industry — without the complications of a border and different currency.
As anywhere in China, Mandarin is the lingua franca used for communication between speakers of different languages. However this area, like most of Yunnan, has several different ethnic groups and most of those have their own language. In Banna, the largest group are the Dai, ethnically and linguistically very close to Thais.
There is a highway south from Kunming into this region, via Pu'er.
A fast bullet train route all the way from Kunming to Singapore has been proposed. Not all the governments involved have reached agreement yet, but as of early 2014 the Chinese part of the route, Kunming-Mengla is in an advanced stage of construction and the link through Laos to Vientiane is scheduled to be complete by 2019.
Stay in a Hani village homestay [dead link] and visit tea plantations, do jungle hikes and try the local foods. 300 yuan per night with three meals included.