King Ramkhamhaeng was not only a valiant and wise ruler, but he also cares a lot about the welfare of his people.

The Thai script (writing) was created by King Ramkhamhaeng, the second son of King Si Intharathit of Sukhothai who had freed Thailand from the Khmer.

King Ramkhamhaeng was also the most successful monarch ever to rule the Sukhothai kingdom.

In order to be truly independent from the influences of the Mon and the Khmer, he created "The Sukhothai Script" in 1283 A.D and it was the earliest Thai writing that was pure Thai.

The Sukhothai Script was actually originated from the ancient Brahmi script of South India called "Grantha".

In 1357, King Li Thai (grandson of King Ramkhamhaeng), created a new script called "King Li Thai script". In 1680, the King Narai script was introduced and it has now become the national Thai script.

Thai consonant class is needed for pronunciation...

The modern Thai script now uses an alphabet of 44 consonants, 32 vowels and four tone marks.

The consonants are then divided into 3 classes, high, medium and low. Please note that the classes are completely arbitrary though.

A low consonant might sound like a high tone and the opposite is also true.

Rippa Sama
http://mythaisensei.com/thai_writing/thai_writing_intro.html