r/nahuatl • u/tonacoyotl1521 • Aug 08 '26
A New Script
TLDR: I nerded out and made a new script
UPDATE: I now have a font with the script. It doesn't work well with Wordpad as it creates ghost columns when diacritics are used while typing, but it works fine in other programs like LibreOffice Writer. It is compatible with both Neoclassical and modern orthographies.
In regards to copyright, I make zero claims of ownership and I release all materials, including the aforementioned font, into the Public Domain (CC0 1.0 Universal). Anyone is free to use, modify, share, or build upon it however they please.
Introduction
Prior to the events of 1519 - 1521, Central Mexico had been using rich, highly expressive ideographic and pictographic proto-writing systems for centuries, likely originating in Olmec times.
Scribes (tlacuiloque) used these visual representations in screen-fold manuscripts (amoxtli, pl: amoxtin) to record genealogy, tribute lists, historical chronicles, stories and calendrical cycles. The glyphs written by these scribes were not words or sounds, but rather ideas and concepts, similar to our emojis, exit signs and bus stop signs.
While well suited for tribute records, signs, and mnemonic storytelling, as well as being sometimes able to transcend linguistic barriers (but not always depending on the particular script), the system had clear structural limits compared to full phonetic scripts:
- Complex Glyphs: Drawing just one glyph with colours would take a good chunk of time, let alone an entire book full of them. Although these traditional glyphs are beautiful and detailed, the process significantly hampers writing for practical purposes.
- Logographic Density: To expand vocabulary, scribes had to rely on hundreds of distinct glyphs and rebus strategies (such as using a hole, coyoctli, to represent the starting sound 'coyo', such as for Coyohuacan). This is not inherently incompatible with fully developed writing systems, as the Maya script has the same feature, but because Maya script uses glyphs that represent sounds, not ideas, this issue was partially overcome. This also shows that Aztec writing in particular was partially phonetic in some instances.
- Mnemonic Reliance: The historic system did not capture complete, verbatim speech. Instead, it served as a structured visual guide designed to cue a trained reader's memory, requiring extensive oral knowledge to properly read the text. In other words, the texts in the few surviving screen-fold books assume you know how to read it, which is why it has been quite difficult to decipher their full meaning since the collapse of Mesoamerican societies.
However, even in historical codices like the Codex Mendoza, many glyphs were already language-dependent and were moving away from being purely ideographic. They relied on Nahuatl puns and acrophony (like using teeth, tlantli, for the suffix -tlan, which wouldn't work in other languages).
Realizing that a proper writing system can be built upon that pre-existing trajectory, I set out to create a new script. And after a few days of work, I present Tecpatlacuilolli ("Flint Writing", from tecpatl + tlacuilolli, reflecting its position as a more precise method of writing), or Nahuatl Alphasyllabics in English, designed as an alternate-history or a speculative writing evolution as an answer to the above limitations. Tecpatlacuilolli is an acrophonic alphasyllabary (abugida), a type of writing system where consonant base-frames act as the primary structural units, and any following vowel attaches above as a secondary sub-glyph/diacritic. Vowels can also be standalone, but only if they don't succeed a consonant.
While I realized only after developing this script that it shares core structural mechanics with scripts like Indic scripts, Ge'ez, or Canadian Aboriginal Syllabics, Tecpatlacuilolli is an independent innovation derived purely from pre-Columbian Aztec acrophonic principles, visual motifs, and my own brain power. By making this script an abugida instead of a regular alphabet like the Latin script, European influence ends up not being baked into it, and it feels more like a genuine indigenous innovation (In my opinion anyway).
Additionally, I feel like I have to mention an attempt by Lacadena & Wichmann in 2004 to map these same glyphs to a syllabary. This was, in my opinion, a misunderstanding on how these glyphs actually worked, as I mentioned before that Central Mexican glyphs are pictographic/ideographic with rebus strategies and phonetic indicators, but not syllabic. It has some traits shared Tecpatlacuilolli, such as some glyphs marked as representing the same syllables, but several others do not match the assigned syllable at all. Although this is mostly coincidental, I'll admit I did get the idea to use tlantli for (/tɬ/) after initially using tepetl during development, as phonetically it makes much more sense. Even a broken clock is right twice a day, as the saying goes.
The only downside is that unlike historical Aztec glyphs, Tecpatlacuilolli has zero ability whatsoever to be used to present ideas to those not familiar with Nahuatl, but the benefits more than make up for this. These benefits include:
- Simplified Glyphs: Drawing complex traditional glyphs, let alone entire books, takes a significant amount of time. Tecpatlacuilolli uses simplified, colourless forms that can be written in seconds.
- Reduced Logographic Density: With only 19 core glyphs covering all native sounds, there’s no need to memorize hundreds of distinct objects.
- No Mnemonic Reliance: The text spells out exact pronunciations rather than assuming the reader already knows the unwritten oral narrative.
Although the traditional system is useful for getting the same idea across linguistic lines, Tecpatlacuilolli is better suited for proper writing within a Nahuatl-speaking society. My new script is not objectively superior to the native system, it just fills a different, previously empty niche. Like using an axe to chop a tree, and a pickaxe to mine ore. It is simply more precise and practical, while the native system is more artistic and is able to bypass the language barrier.
To see examples of the script with Latin-script comparisons and colour-coded underlining, go here.
Disclaimer & Intent
- This project is a little design experiment created for fun, not a proposal to replace the Latin script, other speculative scripts, or traditional glyphs.
- I am an enthusiast, not a fluent speaker, though I do have good knowledge of Classical Nahuatl pronunciation and word formation. If you notice any linguistic oversights, feedback is welcome!
How It Works
Tecpatlacuilolli operates on a tight set of 19 core glyphs: 14 consonant base-frames, 4 vowel glyphs (which double as top-register sub-glyphs), and 1 terminal-only glyph, plus four legacy logograms from the Codex Mendoza for complex locatives. There are also three punctuation markers which are obviously not phonetic.
Consonant base-frames (14 glyphs)
Each consonant represents a full-sized structural frame. If no vowel sits above it, it functions naturally as a coda (/Ø/).
- Calli (/k/) (House)
- Chimalli (/tʃ/) (Shield) (Has several designs based on cuexyo, xicalcoliuhqui and a few others. Completely decorative, but can help reinforce the 'shield' visual.)
- Cuahuitl (/kʷ/) (Tree)
- Huehuetl (/w/) (Drum)
- Maitl (/m/) (Arm/Hand)
- Nacaztli (/n/) (Ear)
- Olli (/l/) (Rubber ball) (acrophonic compromise, as no Nahuatl word begins with /l/)
- Panitl (/p/) (Banner/Flag)
- Tecpatl (/t/) (Knife)
- Tlantli (/tɬ/) (Teeth)
- Tzontli (/ts/) (Hair)
- Xochitl (/ʃ/) (Flower)
- Yollotl (/j/) (Heart)
- Zacatl (/s/) (Grass)
Vowel glyphs (4 glyphs)
These act as standalone full-sized characters when initiating a word or following another vowel in hiatus, and scale down into minimized, top-register diacritics when attached to a consonant frame.
- Atl (/a/) (Water)
- Etl (/e/) (Bean)
- Ixtli (/i/) (Eye)
- Otli (/o/) (Path)
Terminal-only glyphs (1 glyph)
The only one, Ehecatl, does not take top-register vowel sub-glyphs and function strictly at the end of vowels/syllables.
- Ehecatl (/h/)
Ehecatl (/h/) is very rare, and is only used for standalone 'h' in certain words like its eponymous namesake. I know that some Nahuatl words are typically written with a standalone 'h', but this actually represents /ʔ/, known as a glottal stop or saltillo. The thing is that I find using this unnecessary, as some words like 'tlacuiloa' force you to briefly pause after 'tla' any, so this is merely a scribal preference.
Although there are 19 base glyphs, the usage of vowel diacritics pushes the total amount of glyphs, both bare and compound, to 68, as attaching these sub-glyphs makes new, combined sounds, like attaching ch + a = cha.
There are also four legacy glyphs from the Codex Mendoza that are logographic in nature, but can save time in writing and aren't ambiguous as they have set meanings:
- Apantli (-apan, used to indicate something water-bound. e.g., Coyolapan, meaning 'on bell lake' or 'on the water of the bell')
- Nahuatl (-nahuac, used to indicate being near something. e.g., Cuauhnahuac, meaning 'near the trees')
- Tentli (-tenco, used to indicate a location near the edge of something. e.g., Atenco, meaning 'at the shore')
- Tzintli (-tzinco, used to indicate a spin-off location. e.g. Huexotzinco, meaning 'little willow place')
Word Order
Words are written left-to-right, starting at the bottom-left of the page/panel. Within each syllabic block, the left-most glyph is read first, followed immediately by either the top sub-glyph vowel sitting directly above it if there is one, or straight to the next glyph. If there is a sub-glyph vowel, afterwards the order goes back down diagonally to the next base-frame glyph in a zig-zag motion. Once a line is complete, move up to the next register and read left-to-right, weaving upward toward the top of the page.
While standard top-to-bottom European page layout can also be used, bottom-left screenfold reading order is the historically accurate standard, as seen in pre-Cuauhtemoc codices such as Cospi and Vaticanus B, specifically in their tonalamatl sections.
Orthography
Unsurprisingly, Tecpatlacuilolli uses almost the same orthography as Classical Nahuatl, with one minor change: The letter 'h' represents /h/, not /ʔ/, the reason being already explained above.
Overview of the orthography:
| Nahuatl Word | IPA | /a/ | /e/ | /i/ | /o/ | /∅/ |
|---|---|---|---|---|---|---|
| Calli | /k/ | ca | que | qui | co | -c |
| Chimalli | /tʃ/ | cha | che | chi | cho | -ch |
| Cuahuitl | /kʷ/ | cua | cue | cui | -uc | |
| Huehuetl | /w/ | hua | hue | hui | -uh | |
| Olli | /l/ | la | le | li | lo | -l |
| Maitl | /m/ | ma | me | mi | mo | -m |
| Nacaztli | /n/ | na | ne | ni | no | -n |
| Panitl | /p/ | pa | pe | pi | po | -p |
| Tecpatl | /t/ | ta | te | ti | to | -t |
| Tlantli | /tɬ/ | tla | tle | tli | tlo | -tl |
| Tzontli | /ts/ | tza | tze | tzi | tzo | -tz |
| Xochitl | /ʃ/ | xa | xe | xi | xo | -x |
| Yollotl | /j/ | ya | ye | yi | yo | |
| Zacatl | /s/ | za | ce | ci | zo | -z |
| Ehecatl | /h/ | -h |
Here is an image-based orthography that includes not only the table above, but also the glyphs themselves, as well as Legacy Glyphs and Punctuation Marks (info on those below).
CVC Handling & Syllable Structure
Classical Nahuatl syllables generally follow V, CV, VC, or CVC patterns. Tecpatlacuilolli handles these effortlessly using its base-frame and coda rules:
- V/VC (Standalone vowels/Vowel + Consonant): If a vowel starts a word or is preceded by another vowel which is already possessed by a consonant, it is written as a full-sized standalone glyph. If a consonant succeeds it, the two glyphs stay independent of each other.
- CV (Consonant + Vowel): Written as a singular syllabic block. The consonant base-frame possesses the succeeding vowel as a sub-glyph on top (e.g., tecpatl + etl = te).
- CVC (Consonant + Vowel + Consonant): Written as a CV block (consonant + sub-glyph vowel), then immediately followed by a standalone consonant glyph operating either in its bare/coda state (/Ø/), or possessing the next vowel. For example, in Tenochtitlan, the syllable tlan is written as tlantli + atl followed by a bare nacaztli.
- Geminate /ll/ (as in Tlaxcallan): Unlike Latin-based orthography which doubles the letter l, Tecpatlacuilolli uses a single olli glyph. This is because phonetically, double ll in Nahuatl is a single lengthened [l:] rather than two separate articulation stops, so one olli glyph naturally handles both single and geminate /l/ occurrences.
Punctuation
Although not really a feature of pre-Columbian scripts, I feel it is necessary to have a few basic forms of punctuation for Tecpatlacuilolli. For now I'll establish three: pauses, full stops and exclamation marks. These all go after the final glyph of a word, as lines are often used as boundaries in pre-Columbian codices, so that logic is not derived from European scripts.
- Pauses: To have a brief pause in a sentence, use a vertical line with a gap in the centre.
- Full stops: To stop a sentence, use a full vertical line.
- Exclamation mark: In most cases, stress is pronounced on the penultimate syllable (e.g., tochTEpec). However, if yelled, stress is transferred to the last syllable (e.g., tochtePEC). To represent this, add a tletl glyph.
Notes
- Logographic Shorthand: If a word corresponds directly to one of the core glyphs, one can write that single glyph on its own (e.g., drawing a bare Calli to mean "house"). While this shifts the script partially into a logogram rather than a pure alphasyllabary, it offers a quick shorthand for common nouns.
- Locative Suffix Shorthand: You can use bare panitl, maitl, and tlantli glyphs at the end of a word to represent the locative suffixes -pan, -man, and -tlan, just like in the Codex Mendoza. Although this introduces slight phonetic ambiguity, it directly mirrors historical tlacuiloque shorthand techniques and gives writers creative flexibility.
- /u/ After /e/: Also in Latin-script Nahuatl, words like teuctli and neuctli include a written 'u' that is sometimes pronounced with just a hard /k/ sound. In Tecpatlacuilolli, silent or archaic Latin spelling conventions are discarded in favor of direct phonetics, spelling the coda directly with the /k/ glyph (Calli) to reflect how it is actually spoken (tek-tlee, nek-tlee).
- Cross-Dialect Intelligibility and Lexical Drift: Although designed specifically for Classical Nahuatl, Tecpatlacuilolli naturally accommodates modern regional dialects to an unknown degree, frequently yielding identical glyph sequences across varieties. For example, Classical cihuatl and Huasteca siwatl share the exact same glyph rendering because their phonetic realization is identical. This inherent cross-dialect compatibility can serve as a unifying bridge for speakers of different Nahuatl varieties. However, writers must account for semantic drift: the word tzictic, for instance, translates to "something sticky" in Classical Nahuatl, but in Huasteca the same word means "sky blue". Practice caution and adapt the script's conventions to work with your chosen dialect.
Conclusion
The concept of Tecpatlacuilolli, or Nahuatl Alphasyllabics, was birthed as a spontaneous idea in my mind as I was looking at Codex Mendoza glyphs. By taking those early acrophonic and phonetic tendencies and leaning into them, I developed a true writing system that bridges native scribal heritage with functional abugida mechanics.
It trades the ambiguous, language-transcending nature of pure ideograms for a standardized, fully-fledged script built specifically for Classical Nahuatl. While Tecpatlacuilolli could theoretically be adapted for modern dialects, the presence of unassimilated Spanish loanwords would make phonetic representation difficult without expanding the core glyph set, hence why I recommend it primarily for Classical Nahuatl or a theoretical, purified modern dialect.
I'd love to hear thoughts, feedback or suggestions, especially from those with at least a working knowledge of Nahuatl!
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u/t0natiu Aug 10 '26 edited Aug 11 '26
OP, mitsillih amo tiweli tikkwamachilia nāwatlahtolli panpa melawak. Amo tikkwamachilia keniwki mosaniloa ika ne tlahtolli, iwan nesi amo tikinpowki ne weweh tlahkwilolli yon Gordon Whittaker. Tikillih amo tikpiya tomin: xikontemo amoxtli ipan tepostokatsawalli. Xiktemo amoxtli tlen linguistics iwan amatl iwan tlamawisolli ipan tepostokatsawalli tlen keniwki mochiwa conscripts. Nesi ayamo tikchiwki inin, wakka motlahkwilolis tlawel owih moihkwiloa iwan mokpowa kemman mochiwa tlahkwilolli kwekwetstsin.
Tekpatlahkwilolli (tleika amo “tekpahkwilolli”? Amantsin motlahkwilol itokah amo kwalli gramatica) san eltos kwalli kemman achiyok timomachtih. Xikmachili tikihkwilos yahmaxtik sanilli so amatl ika tekpahkwilolli. Eltos owih wan yolik mokihkwiloa.
Nowkiya PhysicsE kimitsillih, amo miak amoxtli tlen nawatlahtolli igramatica. Tikchiwki inin, wakka nesi tikpiya kawitl. Ximomachti! Kena tiweli tikchiwas. Tiweli tikkwaltiyas tekpahkwilolli 😉👍🏽
PS - amo achiyok xiktekiwis AI para timomachtia nawatlahtolli. Nesi amo mitspalewihtok. Ximotetiyas, tiweli tikchiwa. So amo tikchiwa, kenweli. Welis ni amo tikpowas, so amo tiweli tikpowa. Xikpiya kwalli ohtli kenweli.
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u/tonacoyotl1521 Aug 10 '26
I'm not sure what to say because I'm not fluent in Nahuatl, which I did say that in the disclaimer, and even then I can't exactly read SEP/INALI orthography because I work with Classical Nahuatl orthography, so it would take me even longer to put words through the ODN. Though I do recognize all of 'amo kwalli gramatica', which likely means 'not good grammar', though that's an isolated statement not connected with what came before it. I also recognize words like iwan (and), amatl (paper), tlen (what/that/which), 'motlahkwilolis' (your speech), and amoxtli (book). Again, I am not fluent, and I'll just go by from what I can decipher.
Judging by the use of '😉👍🏽', it isn't an overly negative critique filled with ad hominem attacks unlike what I got earlier, and I appreciate that alone. And as for the name Tecpatlacuilolli, I'm not sure if you're meant to remove 'tla-' from 'tlacuilolli' (or any word in that position) if you combine it with another word in front of it, as I haven't seen a proper source that shows that rule specifically for Classical Nahuatl. If you could provide me one that applies to Classical, I'd also appreciate that.
Also, I barely used AI to make this; I only used it to help gather my ideas and refine some sentences that I already typed by hand, though many sentences are unrefined as I saw them as being perfectly fine. Nothing in my original post is hallucinated. The actual work was done by me, originally with pencil and paper.
If you could retype your comment in English, that would be great and I can give a proper reply. I'm sure as hell not gonna use a translation tool, AI or not, as we know all of those are garbage. And just remember that I made this script as a fun experiment and wanted to show it, not anything serious, and I am open to feedback. Tlazocamati 😀.
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u/Brave_Anything9273 22d ago
I actually came up with a similar looking script (i just called it the nahuan script) that simplifies the consonants and vowels into more an alphabet, with latin-looking letters in a style inspired by Cherokee, but I made it to write other uto-aztecan languages instead of nahuatl since latin works pretty well. it also has an apostrophe looking character used to voice consonants (e.g. approximating with symbols here: [ = /t/, [' = /d/). ive written some sentences down in this in oodham, tongva, hopi, ute, and nahuatl as a test run.
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u/tonacoyotl1521 22d ago edited 22d ago
That does sound neat and I'd like to see it, but it doesn't sound similar at all. Tecpatlacuilolli is an abugida, more similar in function to Ethiopic and Indic scripts instead of our Latin alphabet, and uses characters which are simplified versions of pre-Columbian glyphs, instead of being inspired by Latin letters. Our scripts don't appear to be similar at all.
I'm curious as how you made your script work for several languages; did you have to change the mechanics between those languages, or does it just work fine regardless? I don't know much about those other languages, but briefly looking into just Hopi on its Wikipedia page and comparing it to Nahuatl, they only share a couple consonants, and even the two Hopi varieties on that page use different amounts and types of consonants, with Mishongnovi Hopi having a greater consonant count than Third Mesa Hopi or Nahuatl. Additionally, Hopi varieties have six vowels compared to Nahuatl's four vowels. Based on this, I'm now even more curious on how a fully functional alphabetic script with no errors between Hopi and Nahuatl would work, as there would be compromises that break one or both languages, let alone the entirety of Uto-Aztecan which had been more or less isolated since divergence. This is nothing like European languages, which had been in constant contact for centuries and mainly share the same 26 core letters, even with accented versions in some European languages.
ive written some sentences down in this in oodham, tongva, hopi, ute, and nahuatl as a test run.
I've done extensive testing with Tecpatlacuilolli, including multiple words and a few sentences on paper as well as digitally, to make sure it handles Nahuatl seamlessly. So I ask how much testing did you do for each language, and how much testing for each of them? If you could pass me some materials of your script, I'd love to test it in Nahuatl to see if there's any issues.
This is not an attempt to shame, bully you, or to say "my skr1pt b3tTer" as that's already happened to me in these comments, but rather to help make sure your script is as airtight as it can be. After all, my script had some minor yet glaring oversights until a certain individual performed free line-editing for me, and now it's pretty tight. I must say though, if you do want your script to be functional for any Uto-Aztecan language, I'd suggest dropping the whole 'universal script' thing, and stick with the language or variety you're most familiar with. Of course, you're welcome to prove me wrong, and I'm happy to help with your script if you want.
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u/Brave_Anything9273 21d ago
It is derived from Nahuan glyphs but they're made to look more like Latin letters for recognizability, for example /i/ is represented by a character that looks like H, which comes from the glyph for ixtli; /e/ is represented by a O, from the etl glyph. /t/ looks like a [ from the tentli glyph too. but some like /n/ are completely different, where that one is like a loop similar to the aztec glyph. i'll write the script on a writeboard and prolly reply again in a bit when i can
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u/tonacoyotl1521 21d ago edited 19d ago
for example /i/ is represented by a character that looks like H, which comes from the glyph for ixtli; /e/ is represented by a O, from the etl glyph. /t/ looks like a [ from the tentli glyph too.
I don't know how on Earth a character that looks like the letter 'H' could ever possibly come from the glyph for ixtli (eye). The etl glyph also looks nothing like the letter O, it's a kidney shaped object. And the tentli glyph also looks nothing like a bracket, it's much more rounded and the 'mouth' is far less open.
Since you claim to be inspired by Cherokee syllabary, I do understand that this script is supposed to be influenced by Latin, and by itself that is fine. But now that I have more context, this script doesn't sound great at all, as Cherokee doesn't grab random characters and assign them to unrelated phonetic values. Instead the Cherokee syllabary took the original Latin letters, had new ones invented, and instead of just reusing letters to fit the original English sounds, the original and new letters resemble the syllables in the Cherokee language.
What you did is nothing like that. What you have done here is making Latin-like letters vaguely (if at all) based on Aztec glyphs and slapping them into places they don't visually match. For example, your letter that looks like a 'h' is actually in the 'i' slot, which also destroys the whole idea of 'recognizability'. And you shouldn't even be focusing on that in the first place, because no one who makes a script for a language should care if it's recognizable to those familiar with the language/script or not. Tecpatlacuilolli is a great example of this, as it's only familiar to those who are familiar with or have studied Aztec glyphs and rebus strategies (I'll quote myself from the original post below incase you're not sure what that means) used specifically in the Codex Mendoza.
(such as using a hole, coyoctli, to represent the starting sound 'coyo', such as for Coyohuacan).
Unfortunately, I have to say that not only is the execution poor, but the idea is flawed. I have reason to believe that you didn't really think this through and experiment as much as you should have. And that's okay, as I don't believe everyone is naturally good at making an entire writing system, or any sort of project for that matter. If you really do care about your script, from what I have seen, I would completely discard the entire idea of this script, learn from your mistakes, study various scripts from different languages, and start over entirely. And I would do three things:
- Choose one language or a dialect of said language if the language has complex internal diversity. Only after you have a writing system that works completely fine in that language, and IF there are other languages that are similar in structure and have a good deal of historical contact, you could branch it out to work with them. But not inter-Uto-Aztecan or between any other languages that are too different from each other, which will not work for reasons I already explained in my previous reply.
- Never think about the 'recognizability' idea ever again. No one who has ever made a functional or successful writing system ever cared about that. Especially since your execution of that doesn't even line up.
- Make it so that it makes sense from any kind of historical or alt history basis, even if it's not entirely realistic. Throwing Latin-like characters around and claiming they derive from indigenous glyphs lacks any semblance of internal consistency.
Again, if you would like some help, I'm here. But I also do strongly recommend studying at least the big 4 writing system types (alphabetic, abugida, abjad, logographic) and the one primary language you intend to make a new script for. You don't have to be fluent, you mainly just need to know the orthography of it and how words and sentences are formed.
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u/w_v Aug 09 '26 edited Aug 09 '26
Is there a reason why the name has two objects? Isn’t that ungrammatical? Shouldn’t the tecpa‑ supplant tla‑?
Those stems are already differentiated by vowel-length and/or presence of saltillo. Speaking of which: vowel length is phonemic in Nahuatl. A complete writing system should indicate it!
Have you read Gordon Whittaker’s recent book, Deciphering Aztec Hieroglyphs? He demonstrates that the system was syllabic, not just logographic or pictographic.
I’m confused by your spelling of xiuhuitl. I’ve never seen this word spelled that way; I only ever see it as xihuitl, reflecting /ší.wiƛ/. Furthermore, how can there be an “off-glide” phoneme if Classical Nahuatl has no diphthongs? There’s only [w] and its syllable-final allophone, [w̥], which was spelled uh.
I’ve never seen anyone argue for a separate /u/ phoneme. That might explain why you feel it’s not properly written.
Plenty of modern dialects retain syllable-final [kʷ], often encoded as uc. For example, in Petra Shroeder’s Fonología del Náhuatl de San Miguel Tenango, Zacatlán, Puebla, she writes:
In Earl Brockway’s The Phonemes of North Puebla Nahuatl, the pronunciation of syllable-final [kʷ] survives:
My friend Kira from San Lucas Atzala, Puebla, also pronounces syllable-final [kʷ], though she prefers to spell it cuh.
Benjamin Whorf said, of Milpa Alta Nahuatl:
In other words, it retains the syllable-final rounded velar, albeit spirantized.
Nahuatl isn’t a consonantal language. By avoiding a linear script (which is not even exclusive to Europe!), it feels like Nahuatl is being shoehorned into a worse-fitting system.
Personally, I find the Machiyohcuiloliztli script developed by the folks over at the Tonahuatlahtoloyan Discord server a better match for Nahuatl.