Proto-Kra–Dai (typically abbreviated as PKD) is the proposed reconstructed ancestor of the Kra–Dai languages.
Background
No full reconstruction of Proto-Kra–Dai has been published to date, although tentative reconstructions of many Proto-Kra–Dai roots have been attempted from time to time. Some preliminary Proto-Kra–Dai forms have been reconstructed by Benedict (1975) and Wu (2002). Wu (2002) presents a reconstruction of Proto-Kra–Dai phonemes, which is based on data from the Tai, Kam-Sui, Hlai, and Kra branches.
Liang & Zhang (1996) propose a reconstruction of Proto-Kra–Dai () initials and finals, using data from all Kra–Dai branches except for Kra and Jiamao.
Phonology
Proto-Kra–Dai has the finals *-l and *-c, which have been lost in most present-day Kra–Dai languages. It also has the final stops *-p, *-t, *-k and final nasals *-m, *-n, *-ŋ.
Ostapirat (2023) proposes the following consonant inventory for Proto-Kra–Dai, which is relatively simple compared to that of Proto-Tai and other lower-level reconstructions.
Norquest (2020) proposes the preglottalized sonorants *ʔb, *ʔd, *ʔɖ, *ʔɟ for Proto-Kra–Dai, as part of a four-way phonation distinction in Kra-Dai sonorants consisting of preaspirated, voiceless, plain, and preglottalized sonorants. Norquest (2020) also reconstructs velarized initial consonants (*Cˠ-) in Proto-Kra–Dai.
Below is a table of Proto-Kra–Dai pre-syllables and their developments as proposed by Norquest (2020).
Ostapirat (2023) considers many Proto-Tai spirants and rhotics to have developed from the intervocalic lenition of Proto-Kra–Dai medial obstruents. Voicing in the Proto-Tai initial is determined by the voicing of the preceding consonant in the Proto-Kra–Dai form.
Some Proto-Kra–Dai sesquisyllabic consonant onsets reconstructed by Ostapirat (2023) are:
Liang & Zhang (1996) Liang & Zhang (1996) propose the following reconstructions of Proto-Kra–Dai () initials and finals, using data from all Kra–Dai branches except for Kra and Jiamao.
Initial consonants
Plain stop initials
*p, *pw, *pl, *plw, *pr
*t, *tl, *tr
*k, *kw, *kl, *klw, *kr, *krw
*q, *ql, *qr, *ʔ
*b, *bw, *bl, *blw, *br
*d, *dl, *dr
*g, *gw, *gl, *glw, *gr, *grw, *ɢ
Voiced aspirated initials
*bɦ, *bwɦ, *brɦ
*dɦ, *ndlɦ
*gɦ, *gwɦ
*ɣɦ, *ɣwɦ, *ɢɦ, *ʁɦ, *sɢrɦ
Preglottalized initials
*ʔb, *ʔbw, *ʔbl, *ʔblw
*ʔd, *ʔdl, *ʔdr
*ʔm, *ʔml, *ʔmr
*ʔn, *ʔnl, *ʔnr, *ʔȵ, *ʔŋ, *ʔŋw
Voiceless nasal initials
*m̥, *m̥w, *m̥l, *m̥r, *m̥rw
*n̥, *n̥l, *ȵ̥, *ȵ̥w, *ŋ̥, *ŋ̥w
Plain nasal initials
*m, *mw, *ml, *mr
*n, *nr, *ȵ, *ŋ, *ŋw, *ŋr, *ɴl
Prenasalized initials
*mp, *mpl, *mpr
*nt, *ntl, *ntr
*ŋk, *ŋkw, *ŋkl
*mb, *mbl, *mbr
*nd, *ndl, *ndr
*ŋg, *ŋgl, *ŋgr
Glide and liquid initials
*ʔw, *ʔr, *ʔj
*w̥, *l̥, *r̥, *j̥
*w, *l, *r, *j
Fricative initials
*s, *sw, *sl, *sr, *ɕ, *x, *xw, *xl, *xr, *h
*z, *zl, *zr, *ʑ, *ɣ, *ɣw, *ɣl, *ʁ, *ɦ
Initial clusters beginning with fricatives
*xp, *xpl, *xpr, *xt, *xk, *xkw, *xkl, *xklw, *xkr, *xkrw, *xq, *xql
*sp, *spw, *spl, *st, *stl, *str, *sk, *skw, *skl, *skr, *skrw, *sq, *sqr
*zb, *zd, *zdw, *zgr
Vowels and diphthongs
*a, *a, *i̯a, *u̯a, *ɯ̯a
*ə̯, *i̯ə, *u̯ə
*ɛ, *i̯ɛ, *e, *i̯e
*ɔ, *u̯ɔ, *ɯ̯ɔ, *o, *i̯o, *u̯o, *ɯ̯o
*i̯, *u̯i, *ie ,iə, *ia, *iɛ
*u, *i̯u, *ɯ̯u, *ue, *uə, *ua, *uo, *uɔ, *uɯ
*ɯ, *ɯe, *ɯə, *ɯa, *ɯɔ, *ɯu
Lexicon
Ostapirat (2018, 2023) Weera Ostapirat (2018a) reconstructs disyllabic forms for Proto-Kra–Dai, rather than sesquisyllabic or purely monosyllabic forms. His Proto-Kra–Dai reconstructions also contains the finals and . Ostapirat (2018b:113) lists the following of his own Proto-Kra–Dai reconstructions.
Notes: : either or : unspecified consonant and are distinct from and .
Some additional tentative Proto-Kra–Dai reconstructions by Ostapirat (2023) include the following.
Norquest (2020) Norquest (2020) lists the following of his own Proto-Kra–Dai and other lower-level reconstructions.
Lower-level reconstructions
Norquest (2021) provides the following lower-level reconstructions for each branch of Kra–Dai.
Note that like Jiamao, Proto-Be does not distinguish between tone categories B and C, but rather only has an X category, which Chen (2018) names as tone category BC.