Chindamani and reconstruction of Thai tones in the 17th century

Chindamani, the oldest surviving text about the Thai language, contains a direct but equivocal description of Thai orthography and prosody. Combining careful textual study with findings and analytical tools from Comparative Tai, I argue that 17th century Thai had already established a five-tone system that only differs from present-day Thai in two respects. First, some tones were pronounced differently from their present-day counterparts. While Tone 2 and Tone 3 are now low falling and high falling respectively, they were both pronounced with medium pitch. Second, the set of tones allowed on syllables ending in stop consonants was smaller than today. Currently, Tones 2, 3 and 4 can occur in stop-final syllables, but only the first two were allowed in the 17th century.