Notes on the *oo/*oʔ > uu > u Shift in Ch’olan and Huastec(an)


David F. Mora-Marín
University of North Carolina
Chapel Hill



The purpose of this note is to demonstrate that the *oo/oʔ > uu > u shift is not a shared change between Ch’olan and Huastecan, but a set of independent developments. The key piece of evidence lies within Huastecan. More specifically, as Norcliffe (2003:95) has suggested and as is reviewed here, Huastecan did not undergo the change: Huastec did. Chicomuceltec (Kabil), very closely related to Huastec, and argued by Kaufman (1980:101), Kaufman and Justeson (2008), and Robertson and Houston (2015:32) to have differentiated from Huastec during the Postclassic period, does not exhibit the change. This means that Huastec experienced the shift, largely independently, since the beginning of the Postclassic period, many centuries after attestations of the Ch’olan shift in Epigraphic Mayan texts (e.g. Justeson and Fox 1989; Mora-Marín 2009).


I begin with some basic background. Kaufman and Norman (1984) proposed two exclusive vowel shifts in Ch’olan: *oo > uu > u and *ee > ii > i. Those authors characterized these shifts as follows (1984:87):


It is important to note that this change is neither regular nor pervasive, i.e., there are more cases where it does not take place than where it does. However, the change, to the extent it occurs, has a uniform result within Cholan.


They noted too that it affected *oo from both proto-Mayan *oo and proto-Mayan *oʔ, which they proposed had merged into proto-Greater Tzeltalan *oo, as well as *ee from both proto-Mayan *ee and *eʔ, which they proposed had merged into proto-Greater Tzeltalan *ee. Table 1 presents a list of the cases of both proto-Mayan *oo and *oʔ and their reflexes in proto-Ch’olan, according to Kaufman and Norman (1984), with a few additions (e.g. #12, observed by Brown and Wichmann 2004), as compiled in Mora-Marín and Frazier (2021:27).


Table 1. Cases of PM *oo and *oʔ reflected as PCh’ *u or *o.

Item # PM PCh’ Gloss Class Raising
1. *kooŋ-eej *chun-ij in four days adv Yes
2. LM *loot *lut twins n Yes
3. *sootz’ *sutz’ bat n Yes
4. GLM *qootz *kutz wild turkey n Yes
5. *tooŋ *tun stone n Yes
6. GLM *tzoʔn *tzun body hair n Yes
7. GLM *tzoʔtz *tzutz head hair n Yes
8. *ʔoʔq’ *ʔuk’ to cry iv Yes
9. *ʔooŋ *ʔun avocado n Yes
10. *ʔoox= *ʔux= three num Yes
11. *ʔamooch *ʔa=much toad n Yes
12. LM *ʔooj-eel Ch’ol ʔuj-il, Yokot’an ʔuw-i(l) to know v Yes
13. *kooh *choh cheek n No
14. #ch’ool *ch’ol ethnonym (ch’ol) n No
15. *hoonon *honon bumblebee n No
16. *jooj *joj heron n No
17. *joʔl *jol head n No
18. *q-oʔŋ *kon (Ch’ol) let’s go! Expl No
19. LM #koox? *kox pava (bird species) n No
20. *q’oor *k’oy dough n No
21. PM *mooʔ *moʔ macaw n No
22. *nooq’ *nok’1 cloth(es/ing) n No
23. Was+WM *nooq’ ‘animal’ *nok’2 caterpilar n No
24. *ʔook *ʔoch to enter iv No
25. *ʔooq *ʔok foot n No
26. PCM *ʔooŋ-eer *ʔon-i formerly, long ago adv No
27. *ʔoor *ʔoy house-post n No
28. *ʔatyooty *ʔotot home n No
29. PM *poom < MZ *poomɨ *pom copal incense n No
30. PM *tyook’ *tok’ flint n No
31. *t’oot’ *t’ot’ snail n No
32. *ʔaj=tzooʔ *ʔaj=tzoʔ tom turkey n No
33. *xooch’ *xoch’ screech owl n No


Two decades after Kaufman and Norman (1984), Brown and Wichmann (2004) presented a new model of proto-Mayan syllable nuclei based on what they propose are additional vowel correspondences not identified by previous authors. In their model, Kaufman and Norman’s *oo would correspond to their *ooh, and Kaufman and Norman’s *oʔ would correspond to their *oo’ and *oo’h. In addition, Kaufman and Norman’s *ee/*eʔ vowels that experienced the shift would correspond to Brown and Wichmann’s *e/*E/*eh reconstructions (2004:146, 152). Their cases of proto-Mayan *oo’ and *oo’h, thus correspond to the cases of pM *oʔ that merged with *oo in proto-Greater Tzeltalan according to Kaufman and Norman (1984). Moreover, those authors proposed that proto-Mayan *e/*E/*eh shifted to proto-Ch’olan *i in the presence of “a stem-final fricative,” and that proto-Mayan *ooh shifted to proto-Ch’olan *u unconditionally, which means that they treat these processes as distinct from each other. Though Brown and Wichmann (2003) do not say so explicitly, their statement that *oo’ and *oo’h resulted in proto-Ch’olan *uu’ and then u in each of the descendant Ch’olan languages (2003:142-143, Table 9), suggests they consider these to be also unconditioned and exceptionless shifts.


Here I do not intend to review Brown and Wichmann’s (2004) model. This note simply aims to discuss the *oo/*oʔ > uu > u shift, primarily with regard to recent suggestions that it is shared with Huastecan. This suggestion was made by Brown and Wichmann (2004:146), who characterize the vowel-raising shift of *ooh > u as occurring in Huastec, Ch’ol, Chontal (Yokot’an), and Ch’orti’. Although those authors defined a second vowel-raising shift of relevance, their *oo’/*oo’h > u shift, as occurring only in Ch’olan, they cautioned that the three etyma affected by this shift lack cognates in Huastecan (2004:146), so that it cannot be determined, one way or the other, whether Huastecan was involved, the implication being that it may have.


More recently, Lacadena and Davletshin (2013:72), seemingly assuming that Brown and Wichmann’s *ooh > u shift is the only one of relevance to Ch’olan, state that because such shift is shared with Huastecan, and therefore, that “the only solid phonological argument for considering Hieroglyphic Mayan to be a Ch’olan language” would be “*eeh > *ii”; here it should be clarified that Brown and Wichmann’s formulation involves *e/*E/*eh > *ii, not *eeh > *ii. Either way, there is clearly some confusion, which is worthy of clarification. To attempt to do this, I will first review the dataset by Brown and Wichmann of relevance to the *ooh/*oo’/*oo’h shifts those authors redefine in their paper. Table 2 presents the data from Table 1 that experienced the shift, plus a few new etyma proposed by Brown and Wichmann; I have re-transcribed Brown and Wichmann’s <th> as <θ>.


Table 2. Cases of vowel-raising to PCh’ *u, including those exclusive to Ch’olan and those argued to be shared with Huastecan by Brown and Wichmann (2004).

Item # PM (K&N) PM (B&W) Huastecan (B&W) PCh’ (K&N) Gloss Subgroups
1. *kooŋ-eej *koohng- *chun-ij in four days Ch’
2. LM *loot *lut twins Yes
3. *sootz’ *soohtz’ θut’ *sutz’ bat Hua, Ch’
4. GLM *qootz *kutz wild turkey Yes
5. *tooŋ *toohng *tun stone See commentary
6. GLM *tzoʔn *tzoo’n *tzun body hair Ch’
7. GLM *tzoʔtz *tzoo’tz *tzutz head hair Ch’
8. *ʔoʔq’ *oohq’ uk’ *ʔuk’ to cry Hua, Ch’
9. *ʔooŋ *oohng uh/oh *ʔun avocado Hua, Ch’
10. *ʔoox= *oohx oox *ʔux= three Ch’
11. *ʔamooch *moohch *ʔa=much toad Ch’
12. LM *ʔooj-eel *oohj Ch’ol ʔuj-il, Yokot’an ʔuw-i(l) to know Ch’
13. See commentary *oo’hch See commentary *ʔuch possum See commentary
14. See commentary *hoohy or *joohy huy- See commentary slow, sluggish No Ch’
15. See commentary *looht’ See commentary pressed, tightened, cramped See commentary
16. See commentary *poohs puθ- See commentary bubbling, steam, steam bath See commentary
17. See commentary *poohl *pul ‘to burn’ to fry, burn See commentary
18. See commentary *poohl See commentary head, forehead See commentary
19. CM *tz’ul, pM *ch’ol *tz’oohl See commentary to peel, to skin See commentary


Cases #5 and #13-#19 require commentary. First, #5, ‘stone’: though Brown and Wichmann do not make a note of this, the term bears a cognate in Huastecan: <tuhu> in Chicomuceltec, and t’uhu(b) in Huastec (Norcliffe 2003:36, 75). It is therefore another case in which Huastecan agrees with Ch’olan in having u from an earlier *oo (or Brown and Wichmann’s *ooh).


#13, ‘possum’, is problematic. Brown and Wichmann have apparently merged cognates from what Kaufman with Justeson (2003:577–578) consider to be three different semantically-related sets with strong phonological similarities: proto-Mayan *huhty’ ‘possum’; Western Mayan plus Lowland Mayan *ʔuch ‘possum’; and Western Mayan *ʔuhchum ‘possum’. Brown and Wichmann (2004:157, 176) include the Yucatecan, Ch’olan, Tzeltalan, and Mocho’ reflexes of Western Mayan plus Lowland Mayan *ʔuch; the Popti’ (Jakalatek) reflex of Western Mayan *ʔuhchum as ʔutx-, as well as the Tojolab’al and Chuj reflexes of Western Mayan *ʔuchum as ʔuhch- and ʔuch-, respectively. The form the authors cite for Ixil (Greater Mamean), uch, is not listed in Kaufman with Justeson under any of the three reconstructed etyma; Kaufman with Justeson (2003:577) only provide uch’ and juʔch’ for Ixil, as a reflex of their Proto-Mayan *huhty’. Brown and Wichmann do not explain where they obtained their datum. Interestingly, despite merging reflexes from two of the three separate reconstructions, Brown and Wichmann left out the Huastec reflex of proto-Mayan *huhty’, provided by Kaufman with Justeson as ʔuut’ ‘tlacuache’. It appears that Brown and Wichmann’s reconstruction, *oo’hch, is thus an attempt to trace at least two different etymologies back to a single proto-Mayan etymon, but they do not explain how they do this—how their reconciliation works. Their only statement on the matter appears to be their suggestion that “A Cholan language or languages, then, could have influenced development of unexpected vowel quality in the above non-Cholan reflexes of *oo’hch” (2004:157). However, the reconstructed etyma in Kaufman with Justeson all bear a vowel /u/, so there is no reason at this time to suspect that an original *oo (or *oo’h) is involved. Given these uncertainties, this etymon is eliminated below.


Next, #14, ‘slow, sluggish’. Unfortunately, Brown and Wichmann do not provide their sources for this etymon, which they reconstruct as *hoohy or *joohy, and document attestations in Huastec as huy- and Mocho’ as hooy-. It is not attested in Ch’olan, and therefore, there is no way to know whether it experienced the shift in Ch’olan. For this reason, this etymon is eliminated below.


#15, ‘pressed, tightened, cramped’, is reconstructed as *looht’ by Brown and Wichmann, who document attestations as follows: Yucatec lòot’, Mopan lot’-, Ch’ol lut’-, Tzotzil lot’-, Tzeltal lot’-, Q’anjob’al lot’­-, Popti’ (Jakaltek) lot’-, Tojolab’al lot’-, and Chuj lot’. A problem here is found with their entry for Yucatec: it is actually a transitive root lot’ ‘to shrivel up; pull in /stomach/’ (Bricker et al. 1998:173), with the form lòot’ constituting the antipassive stem, the form lóot’ the mediopassive stem, and the form lòʔot’ the passive stem. The Ch’ol form is attested in Aulie and Aulie (2009:54) as lut’ul ‘apretado (squeezed)’. What is interesting is that the Ch’orti’ cognate attested in Hull (2016:260) is lot’-, not lut’, suggesting that this is not an example of the shift. For this reason, this etymon is eliminated too.


Regarding #16, ‘bubbling, steam, steam bath’, reconstructed as *poohs, Brown and Wichmann document attestations in Huastec as puθ-, Ch’ol as pus, Tzotzil as pus, Tzeltal as pus, and Mam as poos- (2004:177); although those authors cite it as an example of the *ooh > u shift they propose for Huastecan and Ch’olan, the /u/ vowel in Tzeltalan poses a problem. The only explanation for the Tzotzil and Tzeltal forms would therefore be borrowing from Ch’olan. Given the lack of sources, however, for now this term will be eliminated.


#17, ‘to fry, burn’, is reconstructed as *poohl by Brown and Wichmann (2004:176), who provide the following dataset: Ch’ol pul, Chontal (Yokot’an) pul-, Ch’orti’ pur-, Teko pool-, and K’ichee’ pool-. However, it also appears in Tzeltal as pul ‘prender, encender (fuego) (to kindle, light (fire))’ (Polian 2019:512). Kaufman and Norman (1984:129) reconstructed this etymon to proto-Ch’olan as a transitive root *pul ‘to burn’ and reported “No outside cognates.” It seems clear that the Tzeltal form is either a cognate or a borrowing. As for the other cases reported by Brown and Wichmann, it is not clear what their sources, actual glosses, or phonological shapes actually are. I have only been able to corroborate a general form <pol-> ‘to fry (an egg)’ in K’ichee’, though the source I consulted (Christenson n.d.:91) regrettably does not distinguish vowel length contrasts. Thus, for now, this form is eliminated.


As far as #18, ‘head, forehead’, is concerned, Brown and Wichmann (2004:176) observe that “This is probably a diffused Maya Lowland form and, therefore, not Proto-Mayan. Nonetheless, it is cited here because it relates to the vowel-quality shift” of *ooh > u. Their attestations include Yucatecan forms, such as Yucatec pòol, Itzaj pol, and Mopan pol, as well as Chontal (Yokot’an) pul. An examination of the Yokot’an entry in Keller and Luciano (1997:197, 512) shows it as pul ‘frente (forehead)’. Kaufman with Justeson (2003:275) only document it in Yucatecan, reconstructing it as proto-Yucatecan *pool. I will include this etymon in the dataset below, and consider it an important addition to the data relevant to the shift, just like the case of ‘to know’, also introduced into the literature on the matter by Brown and Wichmann.


Finally, #19, ‘to peel, to skin’, is complicated, like the case of #13. It appears that Brown and Wichmann have merged cognates from different etyma as reconstructed in Kaufman with Justeson (2003:904­–906), who propose five etyma with the meaning ‘to peel’: Greater Tzeltalan *choʔ, proto-Mayan *q’ol, Central Mayan *tz’ul, Greater K’ichee’an *sol, and proto-Mayan *ch’ol. Clearly, a degree of sound symbolism is involved in at least four of these forms, involving a back vowel /o, u/ and /l/. But more importantly, the reflexes proposed by Brown and Wichmann for their reconstruction *tz’oohl come from different sets: the Ch’ol and Ch’orti’ forms would fit under Kaufman with Justeson’s Central Mayan *tz’ul; and the Mam and Ixil forms would fit under Kaufman with Justeson’s proto-Mayan *ch’ol. Brown and Wichmann present Yucatecan forms: Yucatec tz’òol and Itzaj tz’ol, with only the Itzaj form presented in Kaufman with Justeson (2003:906) under proto-Mayan *ch’ol. With regard to the Yucatec form, it is worth noting that it is attested both as tz’òol in tz’òolol ‘peeled, skinned’ and as tz’óol in tz’óol-pah ‘to peel, get skinned’ (Bricker et al. 1998:53). And with regard to the Ch’ol and Ch’orti’ forms, it is clear that the Ch’orti’ form tz’uhr- includes the passivizer -h-, which has apparently been reanalyzed as part of the root in most contexts, except in the affective derivation tz’ur-tz’a ‘be bald’, where it retains its root shape as tz’ur-. The Ch’ol data provide further justification: it is attested as both ts’ujlel ‘to be peeled’ and ts’ul ‘nude; to peel’ (Aulie and Aulie 2009:103). For now, this etymon must be excluded, but it is absent from Huastecan anyway.


After reviewing the data in Table 2, the following Table 3, with revisions, is offered.


Table 3. Cases of vowel-raising to PCh’ *u, including those exclusive to Ch’olan and those argued to be shared with Huastecan.

Item # PM or later (K&N) PM (B&W) Huastecan PCh’ (K&N) Gloss Subgroups
1. *kooŋ-eej *koohng- *chun-ij in four days Ch’
2. LM *loot *lut twins Ch’
3. *sootz’ *soohtz’ θut’ *sutz’ bat Hua, Ch’
4. GLM *qootz *kutz wild turkey Ch’
5. *tooŋ *toohng <tuhu>, t’uhu(b) *tun stone Hua, Ch’
6. GLM *tzoʔn *tzoo’n *tzun body hair Ch’
7. GLM *tzoʔtz *tzoo’tz *tzutz head hair Ch’
8. *ʔoʔq’ *oohq’ uk’ *ʔuk’ to cry Hua, Ch’
9. *ʔooŋ *oohng uh/oh *ʔun avocado Hua, Ch’
10. *ʔoox= *oohx oox *ʔux= three Ch’
11. *ʔamooch *moohch *ʔa=much toad Ch’
12. LM *ʔooj-eel *oohj Ch’ol ʔuj-il, Yokot’an ʔuw-i(l) to know Ch’
13. pYu *pool *poohl Yokot’an pul ‘forehead’ head, forehead Ch’


Back to Lacadena and Davletshin (2013:72), those authors included examples of etyma such as ‘toad’ (#11), ‘to burn’ (eliminated from dataset due to insufficient reliability of evidence), ‘bat’ (#3), ‘stone’ (#5), ‘to cry’ (#8), and ‘avocado’ (#9) among the examples illustrating a shared change between Ch’olan and Huastecan. As the review of the data so far has shown, only three of these, ‘bat’, ‘stone’, and ‘to cry’, are supportive of such a statement. The case of ‘toad’ is not attested in Huastecan, and the case of ‘avocado’, though attested in Huastecan, actually provides support against the proposed shared innovation, as shown next. In fact, the same may be true of ‘bat’.


At this point I will be more explicit about Huastecan. I will employ the work of Norcliffe (2003), who systematically compares Chicomuceltec (Kabil) and Huastec, the two Huastecan languages, to reconstruct the phonology of proto-Huastecan. According to Norcliffe, the reflex of pM *ʔooŋ ‘avocado’ is attested as uh in Huastec, but as <ou> in Chicomuceltec; and that of pM *sootz’ ‘bat’ is attested as θut’ in Huastec, but as <sot> in Chicomuceltec. These examples led Norcliffe (2003:95-97) to suggest that proto-Huastecan did not experience the shift in question, but instead, that it was Huastec that did. Since the differentiation of Huastec and Chicomoceltec can be dated to the Postclassic period (Kaufman 1980; Kaufman and Justeson 2008; Robertson and Houston 2015), it can be safely argued that the shift in Huastec is not related to the Ch’olan shift, which is documented already during the Early Classic period spellings like su-tz’i for pre-Ch’olan *suutz’ > proto-Ch’olan *sutz’ ‘bat’ on Yaxchilan Lintel 18, dated to CE 526, tu-TUN for pre-Ch’olan *tuun > proto-Ch’olan *tun ‘stone’ on Tikal Stela 31, dated to CE 445, and perhaps in a spelling yu-ta possibly for a reflex of Western Mayan plus Lowland Mayan *ʔoʔt that may have experienced the shift in Ch’olan, resulting in y-ut ‘his/her/its food’, attested as early as CE 100-200 (Mora-Marín 2009:147–148).


Interestingly, pM *q’ab’ ‘hand, arm’ is attested as k’ubak in Huastec, seemingly providing evidence for a shift of *a > u in Huastecan. Nevertheless, it is attested as <kovác> in Chicomuceltec, a form that could suggest that proto-Huastecan actually exhibited a form *k’ob’ak (Norcliffe 2003:180), which then shifted to k’ub’ak ~ k’ubak in Huastec, but was retained with /o/ in Chicomuceltec. What this could suggest is that that Huastec itself experienced a shift of certain cases of proto-Huastecan *o, whatever their source (e.g. earlier *oo, *oʔ, *a), to /u/. And it would appear, consequently, that the only form with *u from a previous *oo in both Chicomuceltec and Huastec is ‘stone’.


Back to the data in Table 1, and assuming for now the reconstructions in Kaufman and Norman (1984), and more generally Kaufman’s (1976, 2015) phonological model for proto-Mayan, a few more observations are worth making here. First, Huastec has preserved some cases of pM *oo that shifted to *uu > u in Ch’olan: pM *ʔoox ‘three’ > Huastec ʔoox, compared to proto-Ch’olan *ʔux=. Second, there are cases where Huastec experienced a change but Ch’olan did not: pM *xooch’ ‘screech owl’, attested in Huastec as tx’uux (Kaufman with Justeson 2003:613), documented by Norcliffe as ts’ux in Potosino and ch’ux in Veracruz (Norcliffe 2003:66), but reconstructed to proto-Ch’olan as *xoch’. Finally, there are also cases of pM *oo that did not shift in either branch, such as pM *kooh ‘tooth (molar)’, pM *q’oor ‘dough’, and pM *ʔook ‘to enter’.


All in all, the evidence suggests that in Huastecan the change was largely restricted to Huastec and not Chicomuceltec, and therefore, that it was late, significantly postdating the *oo > u change in Ch’olan attested by the Early Classic period, perhaps as early as CE 100-200. Also, disagreements among Huastec and Ch’olan in forms that shifted or did not shift further support the contention that Huastec and Ch’olan experienced independent changes; even if Brown and Wichmann’s (2004) model were proven correct —in which case these disagreements would be the result of different correspondence sets— the crucial point here is that Huastec, not Chicomuceltec, underwent the more general shift within Huastecan, which means it was a late, Postclassic change, postdating the earliest attestations of it in Epigraphic Mayan texts. Moreover, Chicomuceltec, attested in Chiapas, and thus the Huastecan language closest to the Lowland Mayan languages, at least during the Postclassic period, is the language that was not affected by the change in question, with one possible exception (i.e. ‘stone’). It is Huastec, at a much greater geographic distance from Ch’olan, that experienced the change of Huastecan *o > u, seemingly under very different circumstances from the Ch’olan *oo > uu > u shift, and almost certainly since the beginning of the Postclassic period. Thus, it is not likely that the change in Huastec was the result of contact with Ch’olan, or vice versa. And there is no reason to exclude cases of the *oo/*oʔ > uu > u shift in Epigraphic Mayan texts as evidence for exclusive Ch’olan innovations, alongside cases of the *ee/*eʔ > ii > i shift.



Aulie, Wilbur H., and Evelyn W. de Aulie. 2009. Diccionario Ch’ol-Español, Español-Ch’ol. Mexico City: Instituto Lingüístico de Verano.

Bricker, Victoria, Eleuterio Po’ot Yah, and Ofelia Dzul de Po’ot. 1998. A Dictionary of The Maya Language As Spoken in Hocabá, Yucatán. Salt Lake City: University of Utah Press.

Brown, Cecil H., and Søren Wichmann. 2004.  Proto-Mayan Syllable Nuclei.  International Journal of American Linguistics 70:128-186.

Christenson, Allen J. n.d. K’iche’-English Dictionary. URL:

Hull, Kerry. 2016. A Dictionary of Ch’orti’ Mayan-Spanish-English. Salt Lake City: The University of Utah Press.

Justeson, John S., and James A. Fox. 1989. Hieroglyphic evidence for the languages of the Lowland Maya.  (Unpublished manuscript.)

Kaufman, Terrence. 1976. Archaeological and linguistic correlations in Mayaland and associated areas of Mesoamerica.  World Archaeology 8.101–118.

—–. 1980. Pre-Columbian borrowing involving Huastec. In American Indian and Indo-European studies: papers in honor of Madison S. Beeler, edited by Kathryn Klar, Margaret Langdon, and Shirley Silver, pp. 101–112. (Trends in Linguistics, Studies and Monographs 16). The Hague: Mouton.

—–. 2015. Mayan Comparative Studies. URL: Accessed January of 2017.

—–. 2017. Aspects of the Lexicon of Proto-Mayan and Its Earliest Descendants. In The Mayan Languages, edited by Judith Aissen, Nora C. England, and Roberto Zavala Maldonado, pp. 62-111. London and New York: Routledge/Taylor and Francis Group.

Kaufman, Terrence, and John Justeson. 2007. The History of the Word for Cacao in Ancient Mesoamerica. Ancient Mesoamerica 18.193–237.

—–. 2008. The Epi-Olmec Language and its Neighbors. In Classic Period Cultural Currents in Southern and Central Veracruz, edited by Philip J. Arnold, III, and Christopher A. Pool, pp. 55–83.  Washington, DC: Dumbarton Oaks Research Library and Collection.

Kaufman, Terrence, with John Justeson. 2003. Preliminary Mayan Etymological Dictionary.

Kaufman, Terrence, and William Norman.  1984.  An outline of Proto-Cholan phonology, morphology, and vocabulary.  In Phoneticism in Maya Hieroglyphic Writing, edited by John S. Justeson and Lyle Campbell, pp. 77-166.  Institute for Mesoamerican Studies Publication No. 9.  Albany: State University of New York.

Keller, Kathryn C., and Plácido Luciano G. 1997. Diccionario Chontal de Tabasco. Tucson, Arizona: Instituto Lingüístico de Verano.

Lacadena, Alfonso, and Albert Davletshin. 2013. Grammar of Hieroglyphic Maya. Advanced Workshop, Brussels, October 29-31, 2013, European Association of Mayanists.

Mora-Marín, David F. 2009. A Test and Falsification of the “Classic Ch’olti’an” Hypothesis: A Study of Three Proto-Ch’olan Markers. International Journal of American Linguistics 75(2): 115-157.

Mora-Marín, David F, and Melissa Frazier. 2021. The Historical Reconstruction of Greater Tzeltalan (Mayan) Vowel Assimilation and Vowel Raising Patterns. Transactions of the Philological Society Volume 00:1–59 (Early View).

Norcliffe, Elizabeth. 2003. The Reconstruction of Proto-Huastecan. MA Thesis in Linguistics, University of Canterbury.

Polian, Gilles. 2015. Diccionario Multidialectal del tseltal. Mexico City: CIESAS.

Robertson, John S., and Stephen Houston. 2015. The Huastec Problem: A Linguistic and Archaeological Perspective. In The Huasteca: Culture, History, and Interregional Exchange, edited by Katherine A. Faust and Kim N. Richter, pp. 19-36. Norman: University of Oklahoma Press.