SHORT HISTORY OF THAILAND
Thailand was the only country in southeast Asia not completely colonized by Europeans, though the French colony of Indochina did control the northeastern province of Nong Khai. Thailand was also know as Siam. After the Japanese invasion in WWII, Thailand sided with the Japs but when the Japs started losing, Thailand switched sides to the allies. In 2017 the very popular, long reigning King of Thailand, Bhumibol Adulyadej died. The current King Maha Vajiralongkorn trained at the Australian military college of Duntroon. He lives in Germany.
On 22 May 2014, the Royal Thai Armed Forces, led by General Prayut Chan-o-cha, Commander of the Royal Thai Army, launched a coup d'état, the 12th since the Thailand's first coup in 1932, against the government of Thailand, following six months of political crisis. More of the Thai coup on Wikipedia
THAI ETHNIC MAP OF THAILAND
Thailand has a mix of cultural influences. In the of northern Thailand the Hmong hill tribes originated over the mountains from China. Coastal areas of southern Thailand were settled by Chinese sailors and Muslims.
At Phang Nga there is a whole floating village of Muslim, Thai citizens which settled there from Indonesia.
The Isan people of northeast Thailand (and around Vientiane, Lao) make up the majority of the Thai population. Their first language and delicious cuisine is a lot different to the Thai's and culture of southern Thailand.
Phu Thai Tai spoken in Laos and Thailand is different from the Isan and the Lao languages. It is spoken in areas where these languages are predominant and has been influenced by them. The Phu Thai are in the majority, hard working rural Thais of north east Thailand. They are skilled farmers and hunter gatherers. More about Phu Thai from Wikipedia
Khmer culture is prominent in the east of Thailand.