Makati Language, the language of Makot or Makata people, is not Indian-based as understood.  Most of the inscriptions found in pillars and stones in India were Sanskrit-based.  Makati, mostly known as Pali-the written recording of Dhamma. (Thai people have never thought Pali was borrowed from India until, a Dr. Bradley in BE. 2413 (1870 AD) told Thai people that the Thai system of writing was derived from India's Palawa writing and that Pali or Makati was from India.)

   The Makati writing, called in Thai as Aksara Dhamma, was designed thousands of years to fit the grammatical rules of Pali semantic.  For example, the positions of vowels, floating vowels and sinking vowels, were only found in Pali writing.  The native writing of Northern and Northeastern Thailand was modified from Aksara Dhamma alphabets and scripted on Bai Larn  or sand stones, or stones. The writing system was used only to record the teaching of the Buddha, Chataka (Buddha's past lives), and related stories.

If the Pali had not belonged to Northern and Northeastern people of Thailand, why did the invention of the writing system support the use in the Pali language?

Similarly, the Aksara Khom, or Khom  (Khmer) alphabets, were invented by Khun Khom Thai  15 years after his brother, Khun Sue Thai, invented the first Thai pictorial writing system in the In Year 1235 (6,735 years ago) called Lai Sue Thai.  Khun Khom Thai's writing was called Lai Khom Thai and now mistaken as  Cambodian.  The alphabets in Lai Sue Thai would read Go, Kho, Ko, Ngo.. with the long /o/ sound while Khun Khom Thai alphabet would read..Ga, Kha, Ka, Nga.. with a short /a/ sound. (1)

 It is evident that a writing system had already existed before the Buddha's time.(2) During his time, Lord Buddha mentioned the words "Pitaka" (books) and "Bai Larn Plao" (empty palm leaves with no writing on it) which show that the writing system had already existed.  It's therefore clear that during the Third Sankayana or Third Revision of Tipitaka, 500 monks must have all the Buddha's teaching put in writing and it took them seven months to complete.  If there were revising the scripture on orally it should not have taken them that long.  The Fourth Revision which it was believed to be the first writtenTipitaka done in Sri Lanka also  took them as long, i.e. eight months.

In Bangkok period, the Revision of the Scripture performed in time of King Rama I  in BE 2331 (1788 AD) also took the monks 10 months to complete recording Buddhist Dhamma in Khom writing on  Bai Larn  (Palm Leaves).

In addition, the uses of language patterns between Pali and Thai/Lao languages are very similar showing that Thai/Lao and Makati people lived together or probably the same ethnic groups.  Many words in Pali were shortened and modified to become Thai and Lao words. (See "The Truth on Language"  by Atama Sirosiri)่.  

Here are some evidences that Pali language was used in Suwannabhumi:

Names of Cities, Rivers, Woods, People in Suwannabhumi  are Pali derivations such as Kukognatee (Kok River); Koranatee (Khong River);   Cheevayanatee (Chee River); Tanamoonnatee (Moon River); Lampakaliwan (Lampang Luang) etc. Pa Himapan (Pan Forest); Chetudorn (Udorn Province) etc. 

Even, male's organ in Thai and Lao language is derived from the Pali word "Kuiha" with /u/ became silent in Lao and /w/ in Thai.

Kalamasutra was based on the story of Kalama villagers when the Buddha told them not to believe easily until they had investigated or thought about it carefully. Kalama was nowadays "Kula" a group of people in the lower Isan of Thailand.

Comparing to George Lucas's Star Wars, we are under the influence of Episode 4, 5, and 6 of world culture in which India was given the credit as the cradle of the world civilization--with the help of British archeologists such as James Prinsep, Sir Alexander Cunningham and those before and after them.  How about the lost Episodes, Episode 1, 2, and 3 in which showing the time when civilization was taken to India.

Supporting Evidence: A recent evidence supporting the claim that Pali was originated and used in Thailand was found by Mr. Krit Kittisak, a student in History of Buddhism in Taiwan from a book  by O. von Hinuber. Seleced Papers on Pali Studies. Oxford: The Pali Text Society,1994, stating that the word "Pali" was known  by the Westerners the first time in the 17th century. Pali language was introduced by M. Simon de la Loubere, who was appointed by King Louis 14th as the first French Ambassador to the Kingdom of Siam (Ayuddha) in the Reign of King Narai the Great in 1687AD (BE.2230).  This book indicated that Pali was originated in Siam (Thailand)  and widely used by the Buddhist monks and the Westerners had the knowledge of Pali from Thailand.  The question is why the Westerners did not have the knowledge of this Pali language when they colonized many Asian countries such as India and Sri Lanka. It is possible that the Pali used in other countries might be limited and not as widely used as in Thailand because the authentic version of Pali was in Thailand.  Even after 2,500 years, Pali is still in used by the Buddhist monks and there are more monks and men who can read and write Pali  in Thailand than in other countries.

FOR YOUR INFORMATION:

(1) In Thailand, there are three systems of date counting: (1) In Year lasting 4,590 years; (2) Lo years starting In Year 4,590 lasting 1190 years, and (3) Buddhist Year beginning at Lo Year 1190 and still  in use until now. Consequently, Thailand has the longest dating counting system nearly 8,000 years ago.

The In  Year was the world's first date counting system, with  the names of 12 years, 12 months ฟืก seven days, initiated by Khun In Kao Kheo  (King In of Green Mountain) to mark his wedding with his bride, Nang Kwag Tong Ma. (Queen Kwag).  After his death, Khun In was respected by his people as Pra In (soon became Sanskitized to be "Pra Indra") with green perplexion due to misunderstanding of his name "Khao Kheo" meaning Green Mountain.  The word In was probably the origin of the word "indies" "Indo" and "India" a possible proof that Khun In's time was the true beginning of eastern civilization. (From Venerable Am Dhammadhatto's The Inscription of Sand Stone Plates of Koobua, 1992).

(2) Gotama Buddha was the Fourth Buddha, millions of years before him there existed already three Buddha, namely (1) Kukuthsandho Buddha, (2) Gonakom Buddha, and (3) Kassapa Buddha.  In the future, the Fifth one, Metraiya  Buddha will come to this world. (Buddha is not his last name but the status of the who gets enlightenment.  Buddha means "the Enlightened One."  You can compare to "Christ" which is not Jesus's last name but his status after achieving his seven brotherhood and become Jesus the Christ.  "Christ" means the "Anointed One.")