Thai Language - History - Old Thai

Old Thai

Old Thai had a three-way tone distinction on live syllables (those that did not end in a stop consonant) and no possible tone distinction on dead syllables (those ending in a stop consonant, i.e. either /p/, /t/, /k/ or the glottal stop that automatically closes syllables otherwise ending in a short vowel).

There was a two-way voiced vs. voiceless distinction among all fricative and sonorant consonants, and up to a four-way distinction among stops and affricates. The maximal distinctions occurred in labials (/p ph b ʔb/) and dentals (/t th d ʔd/), while a three-way distinction occurred among velars (/k kh g/) and palatals (/tɕ tɕh dʐ/), with the glottalized member of each set apparently missing.

The major change between Old Thai and modern Thai was due to the loss of voicing distinctions and concomitant tone split. This may have happened between about 1300 and 1600 AD, possibly occurring at different times in different parts of the Thai-speaking area. All of the voiced/voiceless pairs of consonants lost the voicing distinction:

• Plain voiced stops (/b d g dʐ/) became voiceless aspirated stops (/ph th kh tɕh/). (The glottalized stops /ʔb ʔd/ were unaffected, as they were treated in every respect like voiceless unaspirated stops due to the initial glottal stop. These stops are often described in the modern language as phonemically plain stops /b d/, but the glottalization is still commonly heard.)
• Voiced fricatives became voiceless.
• Voiceless sonorants became voiced.

However, in the process of these mergers the former distinction of voice was transferred into a new set of tonal distinctions. In essence, every tone in Old Thai split into two new tones, with a lower-pitched tone corresponding to a syllable that formerly began with a voiced consonant, and a higher-pitched tone corresponding to a syllable that formerly began with a voiceless consonant (including glottalized stops). An additional complication is that formerly voiceless unaspirated stops/affricates (original /p t k tɕ ʔb ʔd/) also caused original tone 1 to lower, but had no such effect on original tones 2 or 3.

The above consonant mergers and tone splits account for the complex relationship between spelling and sound in modern Thai. Modern "low"-class consonants were voiced in Old Thai, and the terminology "low" reflects the lower tone variants that resulted. Modern "mid"-class consonants were voiceless unaspirated stops or affricates in Old Thai — precisely the class the triggered lowering in original tone 1 but not tones 2 or 3. Modern "high"-class consonants all remaining voiceless consonants in Old Thai (voiceless fricatives, voiceless sonorants, voiceless aspirated stops). The three most common tone "marks" (the lack of any tone mark, as well as the two marks termed mai ek and mai tho) represent the three tones of Old Thai, and the complex relationship between tone mark and actual tone is due to the various tonal changes since then. Note also that the since the tone split the tones have changed in actual representation to the point that the former relationship between lower and higher tonal variants has been completely obscured. Furthermore, the six tones that resulted after the three tones of Old Thai were split have since merged into five in standard Thai, with the lower variant of former tone 2 merging with the higher variant of former tone 3, becoming the modern "falling" tone. (Note that modern Lao and northern Thai dialects are often described as having six tones, but these are not necessarily due to preservation of the original six tones resulting from the tone split. For example, in standard Lao, both the high and low variants of Old Thai tone 2 merged; however, the mid-class variant of tone 1 became pronounced differently from either the high-class or low-class variants, and all three eventually became phonemic due to further changes, e.g. /kr/ -> /kh/. For similar reasons, Lao has developed more than two tonal distinctions in "dead" syllables.)

Early Old Thai also apparently had velar fricatives /x ɣ/ as distinct phonemes. These were represented by the now-obsolete letters ฃ kho khuat and ฅ kho khon, respectively. During the Old Thai period, these sounds merged into the corresponding stops /kh g/, and as a result the use of these letters became unstable.

At some point in the history of Thai, a palatal nasal phoneme /ɲ/ also existed, inherited from Proto-Tai. A letter ญ yo ying also exists, which is used to represent a palatal nasal in words borrowed from Sanskrit and Pali, and is currently pronounced /j/ at the beginning of a syllable but /n/ at the end of a syllable. Most native Thai words that are reconstructed as beginning with /ɲ/ are also pronounced /j/ in modern Thai, but generally spelled with ย yo yak, which consistently represents /j/. This suggests that /ɲ/ -> /j/ in native words occurred in the pre-literary period. It's unclear whether Sanskrit and Pali words beginning with /ɲ/ were borrowed directly with a /j/, or whether a /ɲ/ was re-introduced, followed by a second change /ɲ/ -> /j/.

Proto-Tai also had a glottalized palatal sound, reconstructed as /ʔj/ in Li Fang-Kuei (1977). Corresponding Thai words are generally spelled หย, which implies an Old Thai pronunciation of /hj/ (or /j̥/), but a few such words are spelled อย, which implies a pronunciation of /ʔj/ and suggests that the glottalization may have persisted through to the early literary period.