Reconstruction ofTai languages

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.

It was reconstructed in 1977 by Li Fang-Kuei[1] and by Pittayawat Pittayaporn in 2009.[2][3]



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 [, tɕʰ and ], which are indicated in his work as [č, čh, ž] and described merely as palatal affricate consonants.

Proto-Tai consonants
(Li 1977)
Labial Alveolar Palatal Velar Glottal
Stop Voiceless p t k
Voiceless aspirated tɕʰ
Voiced b d ɡ
Glottalized ʔb ʔd ʔj ʔ
Fricative Voiceless f s x h
Voiced v z ɣ
Nasal Voiceless ɲ̊ ŋ̊
Voiced m n ɲ ŋ
or semivowel
Voiceless ,
Voiced w r, l j

The table below lists the consonantal phonemes of Pittayawat Pittayaporn's reconstruction of Proto-Tai.[2]: 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:

  1. Pittayaporn does not allow for aspirated consonants, which he reconstructs as secondary developments in Southwestern Tai languages (after Proto-Tai split up into different languages).
  2. He also reconstructs a contrastive series of uvular consonants, namely */q/, */ɢ/, and */χ/. No modern dialect preserves a distinct series of uvular consonants. Pittayaporn's reconstruction of the sounds is based on irregular correspondences in differing modern Tai dialects among the sounds /kʰ/, /x/ and /h/, in particular in the Phuan language and the Kapong dialect of the Phu Thai language. The distinction between /kʰ/ and /x/ can be reconstructed from the Tai Dón language. However, words with /x/ in Tai Dón show three different types of correspondences in Phuan and Kapong Phu Thai: some have /kʰ/ in both languages, some have /h/ in both, and some have /kʰ/ in Phuan but /h/ in Kapong Phu Thai. Pittayaporn reconstructs the correspondence classes as reflecting Proto-Tai /x/, /χ/ and /q/, respectively.[4]

There is a total of 33–36 consonants, 10–11 consonantal syllable codas and 25–26 tautosyllabic consonant clusters.

Proto-Tai consonants
(Pittayaporn 2009)
Labial Alveolar Palatal Velar Uvular Glottal
Stop Voiceless p t c k q
Voiced b d ɟ ɡ ɢ
Glottalized ɓ ɗ ʔj ʔ
Fricative Voiceless s (ɕ) x χ h
Voiced z (ʑ) ɣ
Nasal Voiceless ɲ̊ (ŋ̊)
Voiced m n ɲ ŋ
or semivowel
Voiceless ,
Voiced w r, l

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.

Proto-Tai consonantal syllabic codas
(Li 1977)
Labial Alveolar Palatal Velar Glottal
Stop -p -t -k
Nasal -m -n
semivowel -w -j

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.[2]: p. 193 Below is the consonantal syllabic coda inventory:

Proto-Tai consonantal syllabic codas
(Pittayaporn 2009)
Labial Alveolar Palatal Velar
Stop -p -t -c -k
Nasal -m -n (-ɲ)
Liquid or semivowel -w -l -j

Norquest (2021) reconstructs the voiceless retroflex stop /ʈ/ for Proto-Tai. Examples of voiceless retroflex stops in Proto-Tai:[5]

Gloss proto-Tai p-North Tai p-Central Tai p-Southwest Tai
‘lift’ *ʈaːm *r̥aːm *tʰraːm *haːm
‘head louse’ *ʈaw *r̥aw *tʰraw *haw
‘to see’ *ʈaȵ *r̥aȵ *tʰran *hen
‘eye’ *p-ʈaː *p-ʈaː *p-tʰraː *taː
‘die’ *p-ʈaːj *p-ʈaːj *p-tʰraːj *taːj
‘grasshopper’ *p-ʈak *p-ʈak *p-tʰrak *tak

Norquest (2021) also reconstructs a series of breathy voiced initials (*bʱ, *dʱ, *ɡʱ, *ɢʱ) for Proto-Tai. Examples of breathy voiced initials in Proto-Tai:[5]

Gloss proto-Tai p-North Tai p-Central Tai p-Southwest Tai
‘person’ *bʱuːʔ *buːʔ *pʰuːʔ *pʰuːʔ
‘bowl’ *dʱuəjʔ *duəjʔ *tʰuəjʔ *tʰuəjʔ
‘eggplant’ *ɡʱɯə *gɯə *kʰɯə *kʰɯə
‘rice’ *ɢʱawʔ *ɣawʔ *kʰawʔ *kʰawʔ

Some sound correspondences among Proto-Tai, Proto-Northern Tai, and Proto-Southern Tai (i.e., the ancestor of the Central and Southwestern Tai languages) uvular initials given in Ostapirat (2023) are as follows.[6]

p-Tai p-Northern Tai p-Southern Tai
*q- *k- *x-
*ɢ- *ɣ- *g-
*ɢʰ- *ɣ- *kʰ-

Initial velar correspondences, on the other hand, are identical.[6]

p-Tai p-Northern Tai p-Southern Tai
*x- *x- *x-
*ɣ- *ɣ- *ɣ-

Consonant clusters

Li (1977) reconstructs the following initial clusters:

Proto-Tai consonant clusters
(Li 1977)
Labial Alveolar Velar
Unvoiced Stop pr-, pl- tr-, tl- kr-, kl-, kw-
Aspirated unvoiced stop pʰr-, pʰl- tʰr-, tʰl- kʰr-, kʰl-, kʰw-
Voiced Stop br-, bl- dr-, dl- ɡr-, ɡl-, ɡw-
Implosive ʔbr-, ʔbl- ʔdr-, ʔdl-
Voiceless Fricative fr- xr-, xw-
Voiced Fricative vr-, vl-
Nasal mr-, ml- nr-, nl- ŋr-, ŋl-, ŋw-

Pittayaporn (2009) reconstructs two types of complex onsets for Proto-Tai:

  1. Tautosyllabic clusters – considered one syllable.
  2. Sesquisyllabic clusters – "one-and-a-half" syllables. ("Sesquisyllabic" is a term coined by James Matisoff.) However, sesquisyllabic clusters are not attested in any modern Tai language.

Tautosyllabic consonant clusters from Pittayaporn[2]: p. 139 are given below, some of which have the medials *-r-, *-l-, and *-w-.

Proto-Tai consonant clusters
(Pittayaporn 2009)
Labial Alveolar Palatal Velar Uvular
Unvoiced Stop pr-, pl-, pw- tr-, tw- cr- kr-, kl-, kw- qr-, qw-
Implosive br-, bl-, bw- ɡr-, (ɡl-) ɢw-
Fricative sw- xw-, ɣw-
Nasal ʰmw- nw- ɲw- ŋw-
Liquid ʰrw-, rw-

Pittayaporn's Proto-Tai reconstruction also has sesquisyllabic consonant clusters. Michel Ferlus (1990) had also previously proposed sesquisyllables for Proto-Thai-Yay.[7] 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-)
Voiceless obstruent + voiced stop (*C̥.C̬-)
Voiced obstruent + voiceless stop (*C̬.C̥-)
Voiceless stops + liquids/glides (*C̥.r-)
Voiced consonant + liquid/glide
Clusters with non-initial nasals

Other clusters include *r.t-, *t.h-, *q.s-, *m.p-, *s.c-, *z.ɟ-, *g.r-, *m.n-; *gm̩.r-, *ɟm̩ .r-, *, *g.lw-; etc.


Below are Proto-Tai vowels from Pittayaporn.[2]: p. 192 Unlike Li's system, Pittayaporn's system has vowel length contrast. There is a total of 7 vowels with length contrast and 5 diphthongs.

Proto-Tai vowels
(Pittayaporn 2009)
  Front Back
unrounded unrounded rounded
short long short long short long
Close /i/
Mid /e/
Open     /a/

The diphthongs from Pittayaporn (2009) are:


See also: Mainland Southeast Asia linguistic area § Tone systems

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 [1], *B1 [3], *C1 [5], *D1 [7]) and voiced (*A2 [2], *B2 [4], *C2 [6], *D2 [8]) 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 [7], *DS2 [8], *DL1 [9], and *DL2 [10].[4][8] Other Kra–Dai languages are transcribed with analogous conventions.

Proto-Tai tone notation
Type of voicing *A *B *C *D
Voiceless series
(Letter notation)
A1 B1 C1 D1
Voiceless series
(Numerical notation)
1 3 5 7
Voiced series
(Letter notation)
A2 B2 C2 D2
Voiced series
(Numerical notation)
2 4 6 8

The following table of the phonetic characteristics of Proto-Tai tones was adapted from Pittayaporn.[2]: p. 271 Note that *B and *D are phonetically similar.

Proto-Tai tonal characteristics
(Pittayaporn 2009)
*A *B *C *D
Type of final sonorant sonorant sonorant obstruent
Pitch height mid low high low
Contour level low rising high falling low rising
Vowel duration long short
Voice quality modal creaky glottal

Proto-Tai tones take on various tone values and contours in modern Tai languages. These tonal splits are determined by the following conditions:

  1. "Friction sounds": Aspirated onset, voiceless fricative, voiceless sonorant
  2. Unaspirated onset (voiceless)
  3. Glottalized/implosive onset (voiceless)
  4. Voiced onset (voiceless)

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.[9][10][11][12]

Gedney Box template
*A *B *C *DS *DL
A1 B1 C1 DS1 DL1
A1 B1 C1 DS1 DL1
A1 B1 C1 DS1 DL1
Voiced A2 B2 C2 DS2 DL2

Proto-Tai tones correspond regularly to Middle Chinese tones.[13][14] (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.

Sinitic–Tai tonal correspondences
(Written Thai orthography)
Middle Chinese
Chinese name Notes
(Middle Chinese)
*A Unmarked A 平 Level (Even) Unmarked
*B Marked by -่ (mai ek) C 去 Departing Marked by -H in Baxter's notation (mai tho), historically perhaps from [-s] later [-h]
*C Marked by -้ (mai tho) B 上 Rising Marked by -X in Baxter's notation, historically perhaps from [-ʔ]
*D Unmarked or marked by -๊ (mai tri) D 入 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)[15] and Jackson, et al. (2012).[16] Standard Thai (Siamese) words are given below, with italicised transliterations.

Diagnostic words for Tai tones
*A *B *C *DS *DL
1: Voiceless
huu หู ear,
khaa ขา leg,
hua หัว head;
sɔɔŋ สอง two,
maa หมา dog
khay ไข่ egg,
phaa ผ่า to split,
khaw เข่า knee;
may ใหม่ new,
sii สี่ four
khaaw ข้าว rice,
sɨa เสื้อ shirt,
khaa ฆ่า to kill,
khay ไข้ fever,
haa ห้า five;
thuay ถ้วย cup,
mɔɔ หม้อ pot,
naa หน้า face,
to wait
mat หมัด flea,
suk สุก cooked/ripe,
phak ผัก vegetable;
hok หก six,
sip สิบ ten
khaat ขาด broken/torn,
ŋɨak เหงือก gums,
haap หาบ to carry on a shoulder pole;
khuat ขวด bottle,
phuuk ผูก to tie,
sɔɔk ศอก elbow,
khɛɛk แขก guest,
2: Voiceless
pii ปี year,
taa ตา eye,
kin กิน to eat;
kaa กา teapot,
plaa ปลา fish
paa ป่า forest,
kay ไก่ chicken,
kɛɛ แก่ old;
taw เต่า turtle,
paw เป่า to blow,
pii ปี flute,
short (height)
paa ป้า aunt (elder),
klaa กล้า rice seedlings,
tom ต้ม to boil;
kaw เก้า nine,
klay ใกล้ near,
short (length)
kop กบ frog,
tap ตับ liver,
cep เจ็บ to hurt;
pet เป็ด duck,
tok ตก to fall/drop
pɔɔt ปอด lung,
piik ปีก wing,
tɔɔk ตอก to pound;
pɛɛt แปด eight,
paak ปาก mouth,
taak ตาก to dry in the sun,
to embrace
3: Voiceless
bin บิน to fly,
dɛɛŋ แดง red,
daaw ดาว star;
bay ใบ leaf,
baa บ่า shoulder,
baaw บ่าว young man,
daa ด่า to scold;
ʔim อิ่ม full,
(water) spring
baan บ้าน village,
baa บ้า crazy,
ʔaa อ้า to open (mouth);
ʔɔy อ้อย sugarcane,
daam ด้าม handle,
daay ด้าย string
bet เบ็ด fishhook,
dip ดิบ raw/unripe,
ʔok อก chest;
dɨk ดึก late,
to extinguish
dɛɛt แดด sunshine,
ʔaap อาบ to bathe,
dɔɔk ดอก flower;
ʔɔɔk ออก exit
4: Voiced mɨɨ มือ hand,
khwaay ควาย water buffalo,
naa นา ricefield;
ŋuu งู snake,
phii พี่ older sibling,
phɔɔ พ่อ father,
ray ไร่ dry field;
naŋ นั่ง to sit,
lɨay เลื่อย to saw,
nam น้ำ water,
nɔɔŋ น้อง younger sibling,
may ไม้ wood,
maa ม้า horse;
lin ลิ้น tongue,
thɔɔŋ ท้อง belly
nok นก bird,
mat มัด to tie up,
lak ลัก to steal;
sak ซัก to wash (clothes),
mot มด ant,
lep เล็บ nail
miit มีด knife,
luuk ลูก (one's) child,
lɨat เลือด blood,
nɔɔk นอก outside;
chɨak เชือก rope,
raak ราก root,
nasal mucus,
to pull

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.

Tai vs. Kam–Sui tones
Gloss Tai Kam–Sui
pig A1 B1
dog A1 A1
rat A1 C1
ricefield A2 (na) B1 (ja)
tongue A2 (lin) A2 (ma)

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.[17] 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 consonants
Norquest (2007)
Labial Alveolar Retroflex Palatal Velar Uvular Glottal
Unvoiced Stop (C-)p (C-)t ʈ (C-)c (C-)k (C-)q (Cu)ʔ
Voiced Stop (C-)b (Ci/u)d (Cu)ɖ (C-)ɟ (Ci/u)g (C-ɢ)
Unvoiced Fricative f s ɕ x h
Voiced Fricative (C[i])v z ɣ
Voiced Nasal (H-)m (H-)n ɲ (H-)ŋ(w)
Liquid or Semivowel (H-)w, j (H-)l, r

Proto-Southern Kra-Dai medial consonants also include:

Proto-Southern Kra-Dai open rimes
Norquest (2007)
Height Front Central Back
Close /iː/ /ɯː/ /uː/
Mid (/eː/) (/oː/)
Open /ɛː/ /aː/
Proto-Southern Kra-Dai closed rimes
Norquest (2007)
Height Front Central Back
Close /i(ː)C/ /ɯ(ː)C/ /u(ː)C/
Mid /e(ː)C/ /ə(ː)C/ /o(ː)C/
Open /ɛːC/ /aːC/ /ɔC/

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.[2]: p. 64

Proto-Tai syllable structure
(Pittayaporn 2009)
Open syllable Closed syllable
Monosyllable *C(C)(C)V(:)T *C(C)(C)V(:)CT
Sesquisyllable *C(C).C(C)(C)V(:)T *C(C).C(C)(C)V(:)CT


During the evolution from Proto-Tai to modern Tai languages, monosyllabification involved a series of five steps.[2]: p. 181

  1. Weakening (segment becomes less "consonant-like")
  2. Implosivization
  3. Metathesis
  4. Assimilation
  5. Simplification (syllable drops at least one constituent)


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.[18]


Proto-Tai had a SVO (subject–verb–object) word order like Chinese and almost all modern Tai languages. Its syntax was heavily influenced by Chinese.

Lexical isoglosses

Examples of Kra-Hlai-Tai isoglosses as identified by Norquest (2021):[5]

Gloss p-Tai p-Be p-Hlai p-Kra p-Kam-Sui p-Biao-Lakkja
‘beard’ *mumh *mumX *hmɯːmʔ *mumʔ *m-nrut *m-luːt
‘wet field’ *naː *njaː *hnaːɦ *naː *ʔraːh *raːh
‘crow’ *kaː *ʔak *ʔaːk *ʔak *qaː *kaː
‘needle’ *qjem *ŋaːʔ *hŋuc *ŋot *tɕʰəm *tɕʰəm
‘mortar’ *grok *ɦoːk *ɾəw *ʔdru *krˠəm

Examples of Hlai-Be-Tai isoglosses as identified by Norquest (2021):[5]

Gloss p-Tai p-Be p-Hlai p-Kra p-Kam-Sui p-Biao-Lakkja
‘tongue’ *linʔ *liːnX *hliːnʔ *l-maː *maː *m-laː
‘wing’ *piːk *pik *pʰiːk *ʀwaː *C-faːh
‘skin’ *n̥aŋ *n̥aŋ *n̥əːŋ *taː *ŋʀaː
‘to shoot’ *ɲɯː *ɲəː *hɲɯː *pɛŋh
‘to fly’ *ʔbil *ʔbjən *ɓin *C-pˠənʔ *[C-]pənh

Examples of Be-Tai isoglosses as identified by Norquest (2021):[5]

Gloss p-Tai p-Be p-Hlai p-Kra p-Kam-Sui p-Biao-Lakkja
‘bee’ *prɯŋʔ *ʃaːŋX *kəːj *reː *luk *mlet
‘vegetable’ *prak *ʃak *ɓɯː ʈʂʰəj *ʔop *ʔmaː
‘red’ *C-djeːŋ *r̥iŋ *hraːnʔ *hlaːnʔ
‘to bite’ *ɢɦap *gap *hŋaːɲʔ *ʈajh *klət *kat
‘to descend’ *N-ɭoŋ *roːŋ *l̥uːj *caɰʔ *C-ɭuːjh *lojʔ

Proto-Tai prenasalized nasals and Old Chinese

Ostapirat (2023) notes that as in Proto-Hmong–Mien, prenasalized consonant initials in Proto-Tai often correspond with prenasalized consonant initials in Old Chinese (with the Old Chinese reconstructions below from Baxter & Sagart 2014[19]).[6]

Gloss Proto-Tai Old Chinese
collapse *mbaŋ A *Cə.pˤəŋ
daughter-in-law *mbaɰ C *mə.bəʔ
bet *ndaː C *mə.tˤaʔ
ford *ndaː B *[d]ˤak-s
price *ŋgaː B *mə.qˤaʔ-s (?)
hold in mouth *ŋgam A *Cə-m-kˤ[ə]m
early *ndʑaw C *Nə.tsˤuʔ

See also


  1. ^ Li, Fang-Kuei. (1977). A handbook of comparative Tai. Manoa: University Press of Hawaii.
  2. ^ a b c d e f g h Pittayaporn, Pittayawat. (2009a). The Phonology of Proto-Tai (Doctoral dissertation). Department of Linguistics, Cornell University.
  3. ^ Pike, Kenneth Lee; Pike, Evelyn G. Comparative Kadai: Linguistic Studies Beyond Tai. Summer Institute of Linguistics, 1977. p. 16. ISBN 0883120666.
  4. ^ a b Pittayaporn, Pittayawat (2009b). Proto-Southwestern-Tai Revised: A New Reconstruction. Journal of the Southeast Asian Linguistics Society, 2, 121–144.
  5. ^ a b c d e Norquest, Peter (2021). "Classification of (Tai-)Kadai/Kra-Dai languages". The Languages and Linguistics of Mainland Southeast Asia. De Gruyter. pp. 225–246. doi:10.1515/9783110558142-013. ISBN 9783110558142. S2CID 238672319.
  6. ^ a b c Ostapirat, Weera (2023). Proto-Kra–Dai consonants: an outline and outstanding issues. 32nd Annual Meeting of the Southeast Asian Linguistics Society (SEALS 2023), May 18, 2023. Chiang Mai University.
  7. ^ Ferlus, Michel (1990). Remarques sur le Consonnantisme du Proto-Thai-yay. Paper presented at the 23rd International Conference on Sino-Tibetan Languages and Linguistics. University of Texas at Arlington, Oct. 5–7.
  8. ^ Liao, Han-Bo. (2016). Tonal Development of Tai Languages (master's thesis). Archived 1 May 2020 at the Wayback Machine Payap University, Chiang Mai, Thailand.
  9. ^ Gedney, William J. (1972). A Checklist for Determining Tones in Tai Dialects. In M. E. Smith (Ed.). Studies in Linguistics: In Honor of George L. Trager (pp. 423–437). Mouton.
  10. ^ Owen, R. W. (2012). A tonal analysis of contemporary Tai Khuen varieties. Journal of the Southeast Asian Linguistics Society (JSEALS), 5, 12–31.
  11. ^ Manson, Ken. (2009). Prolegomena to Reconstructing Proto-Karen. La Trobe Papers in Linguistics, 12. Available at [1]
  12. ^ Morey, Stephen. (2014). Studying tones in North East India: Tai, Singpho and Tangsa. Language Documentation & Conservation, 8, 637–671.
  13. ^ Downer, G.B. (1963). "Chinese, Thai, and Miao-Yao". In Shorto, H.L. (ed.). Linguistic Comparison in South East Asia and the Pacific (PDF). School of Oriental and African Studies, University of London. pp. 133–139.
  14. ^ Luo, Yong-Xian (2008). "Sino-Tai and Tai–Kadai: Another Look". In Diller, Anthony; Edmondson, Jerold A.; Luo, Yong-Xian (eds.). The Tai–Kadai Languages. Routledge Language Family Series. Psychology Press. pp. 9–28. ISBN 978-0-7007-1457-5.
  15. ^ "Tones of Thai Song Varieties" (PDF). Archived from the original (PDF) on 21 February 2017. Retrieved 17 July 2016.
  16. ^ Jackson, Eric M., Emily H.S. Jackson, and Shuh Huey Lau (2012). A sociolinguistic survey of the Dejing Zhuang dialect area. SIL Electronic Survey Reports 2012-036, SIL International, East Asia Group.
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Further reading