In fact, King Ramkhamhaeng's contribution in creating the first Thai alphabet was a much greater accomplishment than it might seem to have been on the surface. Due to the variety of languages spoken by the "Tai" peoples who formed the Kingdom of Sukhothai, some of whom did not speak tonal languages, the resultant Thai language was a complex combination of vowels and consonants, together with tones, and most certainly would have required a truty great mind to put into written form.
But Sukhothai inself contributed not only to the civilization of nortern Thailand, it also laid the foundation for all successive Kingdoms of Siam by way of philosophical beliefs, benevolent rule, and enormously creative artisan skills.