Thai

What Khmer left in the language

Ayutthaya, the capital from 1351 to 1767, was bilingual in Thai and Khmer from its founding, and Khmer-speaking captives brought from Angkor Thom after the campaigns of 1369, 1388 and 1431 kept it so. Toward the end of the period Khmer fell out of everyday use, and families that had spoken both kept only Thai. The shift carried Khmer words into every part of the language. The Thai of late Ayutthaya, which became Bangkok Thai, used more Khmer words than Tai cognates.

The royal vocabulary, rajasap, was built on Khmer rules and filled out from Thai and from Pali, which came with Theravada Buddhism. Over half of modern Thai vocabulary is derived from or borrowed from Pali, Sanskrit, Mon and Old Khmer.

Why the spelling hides the tone split

Old Thai had three tones on live syllables and a voicing contrast in its consonants. Between about 1300 and 1600 the voicing contrast disappeared, and each old tone split in two: syllables that had begun with a voiced consonant took the lower variant. The six tones that resulted later merged into the five of the standard.

The script still records the older state. Inscriptions in Thai writing appear from around 1292. The consonant classes of modern spelling reflect Old Thai voicing: the low class were once voiced. The three common tone marks, counting the absence of a mark as one, stand for the three original tones. Vowels can be written before, after, above or below the consonant they follow in speech, and silent letters keep original spellings of borrowed words.

Which register suits which listener

Street Thai is spoken between relatives and close friends, without polite terms of address. Elegant Thai is the written and official form. Religious Thai leans on Sanskrit and Pali and is used with monks, and royal Thai, shaped by Khmer, is used for the royal family. The verb 'eat' shows the range. Kin is the ordinary word; rapprathan is formal; chan is religious; sawoei is royal. Rhetorical, religious and royal Thai are taught in schools as part of the national curriculum.

How Central Thai relates to its neighbours

Standard Thai is one of the Chiang Saen languages, with Northern Thai and Southern Thai, inside the Southwestern branch of Tai. It forms a dialect continuum with Lao and Isan and is partly intelligible to their speakers. Most Thais in the regions are bilingual in Central Thai and their own regional language. In the north, a study found that speakers of Kham Mueang have become few.