Some background on the different ethnicities (Karen and Tai Yai) in my community:
Foreword from pamphlet on hill tribes
"The plateau areas of upper Northern Thailand consist of many ethnic groups scattered throughout the region in villages and small communities. Some groups, such as the Karen, migrated here 200-300 years ago. Other groups are more recent arrivals - the Akha, Lisu, Kachin, and Palong - who have migrated within the last 60 years. Some of these groups are considered to be indigenous like the Lawa. Groups or tribes are referred to differently according to their race, language and ethnicity and each has many different names. Some groups are now regarded as flatland Thais such as the Tai Yai, Tai Leu and Tai Kern. Nevertheless, these groups are generalized as hill tribes, mountain people, or people of different cultures.
According to an ethnic survey completed in 2001, which covered 36 locations in five northern provinces in designated areas of the Royal Project Development Center, 15 ethnic groups were identified - the Karen, the Hmong, the Yao, the Lahu, the Akha, the Lawa, the Tai Yai, the Tai Leu, the Tai Kern, the Tai Saem, the Haw, the Kachin, the Palong and the Pruerk."
...
H.S.H. Prince Bhisatej Rajani
Chairman Royal Project Foundation
"Karen"
"In the past Karen lived in accessible areas of the Salawin River in China. They migrated to Burma and Thailand about 200 years ago. In Burma, there are two Karen states. When there was a dispute between the Burmese government and a Karen state or another minority group, it usually produced war. Therefore, many Karen sought refuge in Thailand..."
There are two types of Karen: white Karen and red Karen. Red Karen are also called Karenni. My host family is Karen/ Karenni, and Karenni make up 20-30% of my community. Some of the Karen are known for the neck rings they wear. There is a Karen long neck village less than 5 km from my host family's house.