Proto-Tai is the reconstructed proto-language (common ancestor) of all the Tai languages, including modern Lao, Shan, Tai Lü, Tai Dam, Ahom, Northern Thai, Standard Thai, Bouyei, and Zhuang. The Proto-Tai language is not directly attested by any surviving texts, but has been reconstructed using the comparative method.
The following table shows the consonants of Proto-Tai according to Li Fang-Kuei's A Handbook of Comparative Tai (1977), considered the standard reference in the field. Li does not indicate the exact quality of the consonants denoted here as [t?, t and d?], which are indicated in his work as [?, ?h, ?] and described merely as palatal affricate consonants.
The table below lists the consonantal phonemes of Pittayawat Pittayaporn's reconstruction of Proto-Tai.: p. 70 Some of the differences are simply different interpretations of Li's consonants: the palatal consonants are interpreted as stops, rather than affricates, and the glottalized consonants are described using symbols for implosive consonants. However, Pittayaporn's Proto-Tai reconstruction has a number of real differences from Li:
There is a total of 33-36 consonants, 10-11 consonantal syllable codas and 25-26 tautosyllabic consonant clusters.
Tai languages have many fewer possible consonants in coda position than in initial position. Li (and most other researchers) construct a Proto-Tai coda inventory that is identical with the system in modern Thai.
|Liquid or semivowels||-w||-j|
Pittayaporn's Proto-Tai reconstructed consonantal syllable codas also include *-l, *-c, and possibly *-?, which are not included in most prior reconstructions of Proto-Tai.: p. 193 Below is the consonantal syllabic coda inventory:
|Liquid or semivowel||-w||-l||-j|
Li (1977) reconstructs the following initial clusters:
|Unvoiced Stop||pr-, pl-||tr-, tl-||kr-, kl-, kw-|
|Aspirated unvoiced stop||p?r-, p?l-||t?r-, t?l-||k?r-, k?l-, k?w-|
|Voiced Stop||br-, bl-||dr-, dl-||?r-, ?l-, ?w-|
|Implosive||?br-, ?bl-||?dr-, ?dl-|
|Voiceless Fricative||fr-||xr-, xw-|
|Voiced Fricative||vr-, vl-|
|Nasal||mr-, ml-||nr-, nl-||?r-, ?l-, ?w-|
Pittayaporn (2009) reconstructs two types of complex onsets for Proto-Tai:
Tautosyllabic consonant clusters from Pittayaporn: p. 139 are given below, some of which have the medials *-r-, *-l-, and *-w-.
|Unvoiced Stop||pr-, pl-, pw-||tr-, tw-||cr-||kr-, kl-, kw-||qr-, qw-|
|Implosive||br-, bl-, bw-||?r-, (?l-)||?w-|
Pittayaporn's Proto-Tai reconstruction also has sesquisyllabic consonant clusters. Michel Ferlus (1990) had also previously proposed sesquisyllables for Proto-Thai-Yay. The larger Tai-Kadai family is reconstructed with disyllabic words that ultimately collapsed to monosyllabic words in the modern Tai languages. However, irregular correspondences among certain words (especially in the minority non-Southwestern-Tai languages) suggest to Pittayaporn that Proto-Tai had only reached the sesquisyllabic stage (with a main monosyllable and optional preceding minor syllable). The subsequent reduction to monosyllables occurred independently in different branches, with the resulting apparent irregularities in synchronic languages reflecting Proto-Tai sesquisyllables.
Examples of sesquisyllables include:
Other clusters include *r.t-, *t.h-, *q.s-, *m.p-, *s.c-, *z.?-, *g.r-, *m.n-; *gm?.r-, *?m? .r-, *c.pl-, *g.lw-; etc.
The diphthongs from Pittayaporn (2009) are:
Proto-Tai had three contrasting tones on syllables ending with sonorant finals ("live syllables"), and no tone contrast on syllables with obstruent finals ("dead syllables"). This is very similar to the situation in Middle Chinese. For convenience in tracking historical outcomes, Proto-Tai is usually described as having four tones, namely *A, *B, *C, and *D, where *D is a non-phonemic tone automatically assumed by all dead syllables. These tones can be further split into a voiceless (*A1 , *B1 , *C1 , *D1 ) and voiced (*A2 , *B2 , *C2 , *D2 ) series. The *D tone can also be split into the *DS (short vowel) and *DL (long vowel) tones. With voicing contrast, these would be *DS1 , *DS2 , *DL1 , and *DL2 . Other Kra-Dai languages are transcribed with analogous conventions.
|Type of voicing||*A||*B||*C||*D|
The following table of the phonetic characteristics of Proto-Tai tones was adapted from Pittayaporn.: p. 271 Note that *B and *D are phonetically similar.
|Type of final||sonorant||sonorant||sonorant||obstruent|
|Contour||level||low rising||high falling||low rising|
Proto-Tai tones take on various tone values and contours in modern Tai languages. These tonal splits are determined by the following conditions:
In addition, William J. Gedney developed a "tone-box" method to help determine historical tonal splits and mergers in modern Tai languages. There is a total of 20 possible slots in what is known as the Gedney's Tone Box.
Proto-Tai tones correspond regularly to Middle Chinese tones. (Note that Old Chinese did not have tones.) The following tonal correspondences are from Luo (2008). Note that Proto-Tai tone *B corresponds to Middle Chinese tone C, and vice versa.
(Written Thai orthography)
|Chinese name||Notes |
|*A||Unmarked||A||? Level (Even)||Unmarked|
|*B||Marked by -' (mai ek)||C||? Departing||Marked by -h (mai tho)|
|*C||Marked by -? (mai tho)||B||? Rising||Marked by -x|
|*D||Unmarked||D||? Entering||Marked by -p, -t, -k|
Gedney (1972) also included a list of diagnostic words to determine tonal values, splits, and mergers for particular Tai languages. At least three diagnostic words are needed for each cell of the Gedney Box. The diagnostic words preceding the semicolons are from Gedney (1972), and the ones following the semicolons are from Somsonge (2012) and Jackson, et al. (2012). Standard Thai (Siamese) words are given below, with italicised transliterations.
phaa to split,
khaw ? knee;
may ? new,
|khaaw ? rice,
khaa to kill,
thuay ? cup,
m ? pot,
naa ? face,
|mat ? flea,
haap to carry on a shoulder pole;
phuuk to tie,
kin to eat;
taw ? turtle,
paw ? to blow,
|paa aunt (elder),
klaa ? rice seedlings,
tom to boil;
kaw ? nine,
klay ? near,
cep ? to hurt;
pet ? duck,
tok to fall/drop
tk to pound;
taak to dry in the sun,
|bin to fly,
baaw ? young man,
daa to scold;
?im ? full,
|baan ? village,
?aa to open (mouth);
y ? sugarcane,
daam ? handle,
daay ? string
|bet ? fishhook,
?aap to bathe,
|4: Voiced||m hand,
khwaay ? water buffalo,
|phii older sibling,
ray dry field;
na? ? to sit,
l?ay to saw,
n ? younger sibling,
lin ? tongue,
th ? belly
mat to tie up,
lak to steal;
sak to wash (clothes),
lep ? nail
luuk (one's) child,
Note that the diagnostic words listed above cannot all be used for other Tai-Kadai branches such as Kam-Sui, since tones in other branches may differ. The table below illustrates these differences among Tai and Kam-Sui etyma.
|ricefield||A2 (na)||B1 (ja)|
|tongue||A2 (lin)||A2 (ma)|
In 2007, Peter K. Norquest undertook a preliminary reconstruction of Proto-Southern Kra-Dai, which is ancestral to the Hlai languages, Ong Be language, and Tai languages. There are 28 consonants, 5-7 vowels, 9 closed rimes (not including vowel length), and at least 1 diphthong, *?a(C).
|Liquid or Glide||(H-)w, j||(H-)l, r|
Proto-Southern Kra-Dai medial consonants also include:
Proto-Southern Kra-Dai also includes the diphthong *?a(C).
|Open syllable||Closed syllable|
During the evolution from Proto-Tai to modern Tai languages, monosyllabification involved a series of five steps.: p. 181
This section needs expansion. You can help by adding to it. (November 2014)
Robert M. W. Dixon (1998) suggests that the Proto-Tai language was fusional in its morphology because of related sets of words among the language's descendants that appear to be related through ablaut.