Consonants 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 [, and ], which are indicated in his work as [č, čh, ž] and described merely as
palatal affricate consonants. The table below lists the consonantal phonemes of Pittayawat Pittayaporn's reconstruction of Proto-Tai. 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. Pittayaporn's Proto-Tai reconstructed consonantal syllable codas also include *-l, *-c, and possibly *-ɲ, which are not included in most prior reconstructions of Proto-Tai. Initial velar correspondences, on the other hand, are identical. 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: ;Voiceless stop + voiceless stop (*C̥.C̥-) • *p.t- • *k.t- • *p.q- • *q.p- ;Voiceless obstruent + voiced stop (*C̥.C̬-) • *C̥.b- • *C̥.d- ;Voiced obstruent + voiceless stop (*C̬.C̥-) • *C̬.t- • *C̬.k- • *C̬.q- ;Voiceless stops + liquids/glides (*C̥.r-) • *k.r- • *p.r- • *C̥.w- ;Voiced consonant + liquid/glide • *m.l- • *C̬ .r- • *C̬ .l- ;Clusters with non-initial nasals • *t.n- • *C̬ .n-
Other clusters include *r.t-, *t.h-, *q.s-, *m.p-, *s.c-, *z.ɟ-, *g.r-, *m.n-; *gm̩.r-, *ɟm̩ .r-, *c.pl-, *g.lw-; etc.
Vowels Below are Proto-Tai vowels from Pittayaporn. Other
Kra–Dai languages are transcribed with analogous conventions. The following table of the phonetic characteristics of Proto-Tai tones was adapted from Pittayaporn. 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. 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. 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.
Proto-Southern Kra-Dai 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, *ɯa(C). Proto-Southern Kra-Dai medial consonants also include: • *C(V)-m • *C(V)-n • *C(V)-ɲ • *C(V)-ŋ • *C(V)(i)l • *C(u)r • *p(i)l • *k-l Proto-Southern Kra-Dai also includes the
diphthong *ɯa(C).
Syllable structure Unlike its modern-day monosyllabic descendants, Proto-Tai was a
sesquisyllabic language (Pittayaporn 2009). Below are some possible Proto-Tai syllable shapes from Pittayaporn.: p. 64
Legend: • C = consonant • V = vowel • (:) = optional vowel length • T = tone During the evolution from Proto-Tai to modern Tai languages, monosyllabification involved a series of five steps.: p. 181 • Weakening (segment becomes less "consonant-like") • Implosivization • Metathesis • Assimilation • Simplification (syllable drops at least one constituent) ==Morphology==