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.
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, *ŋ̊, *ŋ̊w • 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==