Sorry for disappearing for long.
Looks like its checkmate 100%. GG leeporter

And to answer, why is there no trace of Siamese language in the region? There is. Just not inscriptions. Just as in the other area of SEA it's looking likely that Malay peninsular was also multiethnic. I think it's quite obvious there were power struggles between AA and AN people's.
But look at this lol
http://malaysiana1.blogspot.com/2009/04/in...s-kelantan.htmlThe Indonesian newspaper Surya claims the youngest of the Sultan of Kelantan, Sultan Ismail Petra's three sons, Tengku Fakhry Petra, beat up his Indonesian model and actress wife Manohara Pinot.
The paper from Surabaya in Java reported that Pinot's mother Daisy Fajarina claimed the Kelantan prince was abusive and violent towards his wife.
Tengku Fakhry is believed to be contemplating legal action against the paper and his wife's family, for "lying and slandering his family".
Tengku Fakhry married Pinot, 17, in 2007. She is of Bugis and French descent and the younger of two daughters of Daisy and her ex-husband French businessman Reiner Pinot.
[Actually, Reiner is her stepfather. Her real father was of British American ancestry, and he was Daisy's first husband]
Tengku Fakhry, Daisy claimed in the newspaper, met his future wife at a dinner with the current Malaysian Prime Minister Datuk Seri Najib Razak (who was then Deputy Prime Minister) in late 2006.
Najib, before his marriage to First Lady (there is no official title of First Lady in Malaysia, and First Lady generally refers to the wife of the CEO of Malaysia) Datin Seri Rosmah Mansor of Kuala Pilah, Negeri Sembilan, was married to Tengku Zainah Tengku Iskandar, an aunt or cousin of Tengku Fakhry.
The Kelantan royal house is one of the oldest in Asia and the world, and is descended from the kings of the Mon (also called Talang or Bulang) people of Indochina.
Kelantan, the country of the Mon people, was once a mighty kingdom covering all of modern-day Kelantan and Thailand.
However, it shrunk in size over the centuries. Thailand north of Ranong became the Mon kingdom of Funan.
The Isthmus of Kra, sans the modern-day Thai provinces of Yala, Narathiwat and Patani, became part of the Hmong (Miao) kingdom of Kedah and later split to become the Hmong (Miao) kingdom of Ligor (Satun).
The modern-day Thai provinces of Yala, Narathiwat and Patani split from Kelantan to become the Mon kingdom of Patani.
After 1200, the Thais who were in modern-day Laos, gradually subdued Funan (also known as Suvarnabumi), and turned it into Thailand (or Siam prior to the end of World War Two).
The Thais absorbed the Mons of Funan.
The Thais also subdued Ligor and absorbed the Hmong (Miao) people.
Around 1720, Thailand forced Patani, Kedah and Kelantan to become its "protectorates".
Patani, Kedah and Kelantan had long been protectorates of the mighty kingdom of Johor in the south of the Malay Peninsula, but fell under the Thai sphere of influence as the Sultans of Johor were busy fighting Dutch invaders in the 18th century.
Thailand cut the kingdom of Perlis out of Kedah in 1821. Perlis, ruled by a nephew of the Sultan of Kedah, also became a "protected state" of Thailand.
At the same time, Thailand forced Johor's protectorate Terengganu, ruled by a branch of the Johor royal house, which is as old as Kelantan's, to become its "protected state", too.
In 1909, Britain which had then taken control of the mainland (Malay Peninsula) portion of the Johor Empire, took Perlis, Kedah, Kelantan and Terengganu out of the Thai Empire and put them back into Malaysia (the mainland portion of the Johor Empire under British control).
The Kelantan royal house is famous for producing prominent Malaysian technocrats, politicians and businessmen.
They include ex-Foreign Minister Tengku Ahmad Rithauddeen Ismail, ex-Finance Minister Tengku Razaleigh Hamzah, ex-Proton (National Automobile Company) CEO Tengku Mahaleel Ariff, businessman Tengku Azman Sharifadeen, and conservationist Tengku Zainal Adlin Mahmud.