QUOTE (Leeporter @ Jan 12 2012, 10:42 PM)

How does he know his ancestor spoke Mon-Khmer before switching to Tai? 
I am a southerner and I've tried to listen to Khmer, Mon, Malay, even Tamil and I didn't feel any common between those languages and southern Thai language.
If you see some common words between southern Thai and Khmer or Mon, it deosn't mean that they spoke Mon-Khmer.
Mon and Khmer may adopted those words from Southern Thai when the Brahman moved from southern thailand to east and north. 
PS> After many year of Central Thaification, Southerners still find it hard to speak Bangkok language, how easy it is for Sukhothai to whip all the previous language of Nakorn Sridhamarat and changed them to speak Tai without any trace?
Like I said before. It's possible for the whole group of people will change their language. Especially if they are minority live in a city (not living like a tribal people). Tai Ahom, now they speak Assamese, Indo-European language. The king, elite people turn to speak Assamese which spoken by religion officers (Bramhins) and the whole common Tai Ahom people change to speak Assamese too.
(Btw, If someone wanna know what Pure Tai language is, it should look at Tai Ahom, becos it's not affected by Buddhism and Hinduism.)
As I know Irish in Ireland speak English, very less of them speak Irish language.
This is what that Siamese guy says.
QUOTE (sonofgunongjerai @ Apr 19 2009, 06:06 AM)

The City of Ayutthaya and its relation with Native Siamese
This city had fast developed and began to be known as "Siamese City" in the region around and in the West. Its influence reached deep south taking over the role of Sukhothai Empire. Siamese Kingdom in Perak (Gangga Nagara), Johor (Khlang Keo), and Pahang (Indrapura) had close relationship with Sri Ayutthaya. Those three city-states ethnically are of Mon-Khmer stock, not Tai.
Sejarah Melayu or Malay Chronicle (1612 CE) written by Tun Sri Lanang had stated that the city-state of Ganggayu (Khlang Keo) was build by the aborigines of Siam Empire who are the Mon-Khmer people (I would only love to relate this ethnic with Mon people, not Khmer because they are distant people). The city of Khlang Keo was said located at the upstream of Johor River. The city had forts made of black stone and its ruler is Raja Chulan, who is the emperor at that time because all of the kings in the East paying tribute to him". The Siamese Kingdom (Mon-Khmer ethnic) of Gangga Nagara and Khlang Keo was subdued by the King of India sub-continent while Indrapura Kingdom was subdued by Malacca Kingdom (Malays). Although Tun Sri Lanang had failed in stating the date for the sake of historical fact, but he had insist that Khlang Keo or the City-State of Aborigine of Siam still exist when he finished writing the chronicle.
The code of Siam Law called Kot Monthieraban (1360 CE) stated that there is a city-state paying tribute to Siam empire known as Wurawari Kingdom, and it is located in Old Johor or Khlang Keo (Ganggayu). The history sholars had different views concerning the name of the city-state but they are not denying the existance of this native Siamese kingdom in Old Johor.
Native Siamese are not to be confused with Tais. They are Mon-Khmer people and not Malay nor Proto-Malay. This had proved that native Siamese already exist and founding kingdoms in Malayan Peninsula, living in peace and sometimes involved in wars especially with Malacca Kingdom (Malays). There are also other native Siamese kingdoms like Patani, Kelantan, Kedah, Gangga Nagara, and etc whether under the Siam influence or not. They exist before the emergence of Siam empire, and Malacca kingdom.