Not considering logographic systems like Chinese, and outside Cuneiform (not sure if that is a logo system or something else), it appears at first glance that many of the world's writing systems started out without giving vowels a first-class-citizen position in the script. In Brahmic script, from which many of the Indian-continent and Southeast Asian scripts are derived, and even in Devanagari, the vowels are secondary diacritics on the abugida symbols, which are based around consonants. In the Semitic languages like Arabic and Hebrew, from which the Greek/Latin alphabets were at least partially derived (via Hebrew), they leave out the vowels altogether, only adding them to the script through basically diacritics later. I could be wrong on my "facts", but if so, please correct; I am just ballparking here.

Is there anything significant about that fact? Why would we go from logographic to consonant-based (putting vowels secondary or nonexistent) to vowels and consonants on equal footing like in English? What is it about vowels that makes us ignore them or attach them as diacritics? What is it about consonants that makes us think "these are the things we need to keep track of"? Has anyone thought about this, or does anyone have any theories on why it evolved like that? Or is it just completely arbitrary?

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    Given the somewhat unique consonantal structure of Semitic roots, abugidas and abjads make a certain amount of sense for Semitic languages – you can (usually, more or less) recognise the root by the base letters, only having to look to the vowel diacritics to determine the specific form of the root. This is also, to some extent, the case in Proto-Indo-European – but by the time Brahmic scripts came along, it wasn’t the case anymore in the Indic languages they were made for, due to sound changes changing and obscuring original skeletal root consonants. Apr 20, 2023 at 23:24
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    If you look at the four or so "original" writing systems (ones that we think were invented from scratch rather than being inspired by something else), Han characters are logographic, cuneiform treats vowels and consonants about equally, Mayan hieroglyphs treat vowels and consonants about equally, and Egyptian hieroglyphs record only consonants. One out of four isn't that much.
    – Draconis
    Apr 21, 2023 at 0:26
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    Bcs wrtng s hrd. Stp mkng m wrt s mch. Apr 21, 2023 at 20:43
  • 2
    An answer to this question requires consideration of how illiterate people think about the sub-word parts of language. Is it the case that "syllable" is the natural unit that a thinker-about-language comes to? Depends on the language, I think. In a language like Chinese, it's practically unavoidable; but in Salish syllables are stylistic matters.
    – jlawler
    Apr 21, 2023 at 21:49
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    Greek script is derived from Phoenician, not Hebrew.
    – Neith
    Apr 23, 2023 at 15:59

5 Answers 5


In Ancient Egyptian, like many Afro-Asiatic languages, the consonants generally determine the root of a word, while the vowels inflect it. Sāḏam means "to hear", saḏma means "might hear", sāḏim means "hearing", and so on. So when you start repurposing the picture of an ear to mean these sounds in other contexts, rather than only the word for "hear", what sounds should it represent? The obvious answer is the consonants s-ḏ-m, rather than any of the vowels. Those consonants are the only thing that's consistent between the different forms. As a result, the writing system ended up only recording consonants. When Semitic-speaking peoples adapted this system to their own Afro-Asiatic languages, they also only recorded the consonants, because that's what the system already did, and because the consonants were the most important thing for conveying meaning in their languages too (determining the root rather than the inflections).

In Devanagari and its descendants, on the other hand, it has nothing to do with the language in question. Every language on earth has more consonants than vowels. It's easier to have many base forms, and fewer diacritics, than the other way around. Thus consonants are the base forms and vowels are the diacritics.

Since every language has more consonants than vowels, it also makes sense that we never see writing systems that completely ignore the consonants, while we do see writing systems that completely ignore the vowels. One is possible, the other probably isn't. (_m_g_n_ r__d_ng _ngl_sh w_th__t v_w_ls, _e__u_ _ea_i__ E__i__ _i__ou_ __e _o__o_a___.)

Imagine reading English without vowels, versus reading English without the consonants.

  • 4
    "Every language has more consonants than vowels": A possible counterexample is Kirikiri with 6 consonants and 7 vowels (but two of the vowels are highly unusual ones) Apr 21, 2023 at 8:12
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    In the spirit of maintaining a Q&A site on linguistics, I made a question out of this: linguistics.stackexchange.com/q/46488/9781 Apr 21, 2023 at 10:17
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    @Barmar Counterpoint: Tone. English does not indicate tone of voice except very clumsily with things like italics, special punctuation, and parenthetical comments spelling out, either fully or abbreviated, exactly what is meant.
    – No Name
    Apr 21, 2023 at 16:56
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    @Barmar The role of a word in a sentence usually has more redundancy than the meaning of the word. For example, in Akkadian, the word at the end of a sentence is practically always a verb. If you get rid of the vowels, you might lose some nuances like whether it's a past verb versus a future verb, but you'll still know what it means.
    – Draconis
    Apr 21, 2023 at 18:29
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    @Yakk-AdamNevraumont English spelling is known to be a mess. But other European languages are much more regular.
    – Barmar
    Apr 22, 2023 at 4:01

One reason is that vowels are much less important for distinguishing words than you might think. Years ago I did an analysis of the Carnegie Mellon Pronouncing dictionary. I asked what would happen if all of the vowels of English were replaced with a single vowel — call that language Unglush.

There are lots of ways you could compare the two languages, but this one stood out to me at the time:

  • In English, 0.0071% of pairs of words are homophones
  • In Unglush, 0.011% of pairs of words are homophones

You only get 1.48 times more homophones when you eliminate all of the vowel contrasts of English.

So as a practical matter, vowels aren't very important for telling words apart. (In English, and you would find similar results in other languages.)

So if your orthography doesn't have vowels at all, it's not going to be that much of a problem.

English of course has taken the alternate route of having vowels but using them in (ahem) creative ways (E.g., “English is hard but can be learned through tough thorough thought, though.”)

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    Ys, nd t’s nrmlly pssbl t rd nglsh wtht vwls ltgthr. Apr 21, 2023 at 13:34
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    @Araucaria-him weea one nee at lea one cooa to mae an see of te voe aloe. Apr 21, 2023 at 13:55

There are several considerations; in some cases they might have acted jointly, and/or sequentially.

Preface: syllabaries

As far as I can tell, the default structure for a script is a syllabary (where each sign represents a syllable), such as Cherokee, Linear B, or Japanese kana.
When scripts are invented by people not previously familiar with other scripts, or when they are simplified from a previously more complicated script, the result is usually a syllabary rather than an abjad (a consonantal script) or an abugida (a mainly-consonantal script with vowel diacritics).

So why are there so many abjads and abugidas? And where do alphabets come in?

Consideration 1: Afro-Asiatic grammar

As mentioned in the answer by Draconis, Afro-Asiatic languages have a grammatical system where word roots mainly consist of consonants, and grammatical inflections (as well as some forms of word derivation) are mainly indicated by vowels between those consonants.
In such a system, it makes sense to only indicate consonants in the script, to point out the root instead of focusing on the specific grammatical form.

Afro-Asiatic languages include Ancient Egyptian, as well as Semitic languages, including Phoenician and Ugaritic. All three of those were early adopters of consonantal scripts; the last two possibly borrowed the concept from the first.
(Akkadian was also a Semitic language, but Sumerian was not, and Akkadian script was borrowed from Sumerian. Akkadian cuneiform is not consonantal, but logosyllabic, somewhat similar to Japanese script in structure; some of its descendants, such as Hittite cuneiform, are almost purely syllabic.)

Note that Egyptian hieroglyphs were not a direct consonantal script; each hieroglyph typically represented a particular word, and by extension the consonantal structure of that word, which could be shared with different words.
Later some hieroglyphs evolved to only represent some consonants of a word, such that eventually there was at least one way to write every consonant by itself (allowing writing down arbitrary sequences of consonants, such as foreign names), but multi-consonantal symbols (which represented many consecutive consonants) persisted throughout the script's history.
There were also determinatives, signs that related to the meaning of the word being represented rather than its sound. (An approximate English comparison is the use of capital letters for proper names.) Egyptian was a complicated system, and the hieroglyphs in particular (there were simpler shorthand forms) actually became more complicated in later periods.

In turn many other scripts are ultimately descended from the Phoenician script and/or its close relatives (a scantily attested script close to the common ancestor of those relatives is traditionally designated as Proto-Sinaitic); some of them (notably Greek) had innovated vowel letters on the same level as consonant letters, and the script we use in English descends from one such branch.
Others did not do that, and remained purely consonantal, or had vowel diacritics rather than letters.

To the best of my knowledge, all non-modern alphabets, with one possible exception (Irish ogham), are either the result of vowel letter innovation in previously consonantal (or vowel-diacritical) scripts, or descended from such a result.
(There are, of course, many modern alphabets that are not directly descended from previous scripts, invented by people who were familiar with existing alphabets and assumed that an alphabet was the default writing system. It is possible that Irish ogham was an ancient case of the same idea.)

Consideration 2: default vowels

So, now we have a popular consonantal script (Proto-Sinaitic/Phoenician), and many languages, including many non-Afro-Asiatic languages, are borrowing the script (or one of its descendants) for their own use.
In non-Afro-Asiatic languages, roots are (usually) not made out of consonants, and grammatical inflections feature both consonants and vowels. So a purely consonantal script is inconvenient; some representation of vowels is useful.
Some scripts, such as Greek, Yiddish, and Hangul, used separate vowel letters; others did not. What could have influenced the choice?

One likely consideration is default vowels.

In many languages, a single vowel, usually /a/, accounts for the majority of vowels in text. In such languages, it makes sense for a consonantal character, such as /b/, to represent the syllable /ba/ rather than just the consonant /b/; then the comparatively rare cases where the consonant is followed by a different vowel can be represented by special signs for that vowel.
(Such a setup is usually referred to as an inherent vowel; it requires special handling for consonant clusters, because just writing the consonants next to each other would represent separate syllables.) This was the option chosen in Brahmi and Kharosthi, both scripts for Indo-Iranian languages with a strong default vowel tendency, and the (many) Indic scripts descended from those two consequently also frequently use this setup.

Note that the "special signs for that vowel" do not have to be diacritics; there are some scripts (both within and outside the Indic family) that use this setup but are otherwise alphabetic, with full vowel signs.

Side-note: Afro-Asiatic vowel representation

As previously noted, Afro-Asiatic languages tend to have grammatical systems that make vowel representation less obviously required than for most other languages.
However, even in those cases, having some way to represent vowels was useful (especially for liturgical texts, where an exact reading was considered to be important).

As such, vowels had to be represented, but since the consonants were more important (featuring in roots rather than merely in inflections), the vowels could be relegated to diacritics.
This had happened independently in Hebrew (niqqud), Arabic (harakat), Ge'ez (where the vowel diacritics fused with the consonants, resulting in a Brahmic-like syllabary), and several other Semitic scripts.

A common alternate option was to use the letters for consonants that had grammatical correspondences to vowels, and/or became vowels by sound changes; this especially involved the so-called "semivowels" /j/ and /w/, which corresponded to vowels /i/ and /u/.
This option is known as matres lectionis [Latin for "mothers of reading"], and is a major stepping stone towards an alphabet, especially when borrowed into a non-Afro-Asiatic language; in fact it had been suggested that the Greek alphabet is based on a variant of Phoenician that had already made much use of such a system.
Other cases of this kind of system developing into a full alphabet include Yiddish, Sorani, and Mandaic (a Semitic language).

Consideration 3: there just aren't that many vowels

It might surprise speakers of Germanic languages (which are known for particularly large inventories of phonemic vowels) that most of the world's languages have just five or six distinct vowel phonemes (and many have even less).
This lets writing systems get away with using diacritical signs to represent vowels, because there are few enough vowels for visually distinguishable diacritical signs.

Note that the languages that the alphabets were invented for typically also had single-digit numbers of vowel phonemes, and consequently single-digit numbers of vowel letters.
This meant that languages with double-digit vowel inventories had to get... creative... with representing their vowels right. (Common solutions were digraphs/trigraphs, as in English and French, and diacritics, as in Hungarian and Vietnamese.)
But it also meant that abugidas, where vowels were diacritics in the first place, could hardly deal with large vowel inventories at all. This is part of the perceived dominance of alphabets: they're a lot more convenient when your language has a lot of vowels!

However, Afro-Asiatic (especially Semitic) languages don't usually have all that many vowels (and many of the vowels they do have are often associated with specific consonants and written as such), so abugidas do not get as much pressure from alphabets.
In theory, languages with small vowel inventories could use an abugida even if they did not historically borrow one from elsewhere; in practice, this almost never happens outside of the Arabic and Indic zones of influence, because most of the world's major languages use alphabets, so inventors usually default to an alphabet. One example of an invented abugida is the Mwangwego script, for the Chichewa language of Malawi (5 vowels).
As it happens, Australian Aboriginal languages tend to have a lot of consonants but very few vowels (usually just three), making them nearly ideal candidates for an abugida. I wonder if any Aboriginal inventors had came up with an abugida script by now...

Postscript: the other side

As mentioned in the question (and in the answers), there are many writing systems where the consonants are full letters, but the vowels are merely diacritics.
However, in principle, there could also be a script with full vowels and diacritic consonants.

And it turns out that there is in fact just such a script! In the Pahawh Hmong script of northern Laos (said to have been invented by an illiterate Hmong man in the 20th century), the vowels are full letters, but the syllable-final consonants are always diacritics, and so are some of the syllable-initial consonants (it's complicated).

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    Why is Ogham a possible exception? It’s not exactly certain which script Ogham was originally modelled on, but the main contenders (Latin alphabet, runes, Greek alphabet) are all scripts that developed from consonantal scripts that grew full vowels, so Ogham would be too. Apr 21, 2023 at 21:16
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    @JanusBahsJacquet Ogham does not very much resemble any other script; its letters are an a priori invention, and its order does not appear to have any basis in previous scripts either. Most (all?) other alphabets prior to the 19th century were direct descendants of older scripts in form as well as function. Ogham, meanwhile, very much looks like an invention of someone who decided to make an alphabet because the neighbours all had those. (IIRC the main alternative theory is that it is originally cryptographical?) Apr 21, 2023 at 22:09
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    I doubt that Arabic harakat were invented indepently of Hebrew niqqud: The were Jewish communities present all around the Arabic world in medieval times. Same for Ge'ez. Apr 22, 2023 at 9:33
  • I believe that nearly all phonetic writing systems, with the notable exceptions of the Japanese kana and Korean Hangul, are thought to be natural evolutions of Sumerian cuneiform. So it may be accurate just to say that the first people to use letters to represent single sounds didn't bother to write vowels because they weren't important to their languages, and everyone down the line had to innovate their own vowels, and only one branch of the script family (Greek, whence Latin and Cyrillic) ended up with full vowel letters. Mar 1 at 19:14

Ontogeny tends to recapitulate phylogeny. Phonetic (not logographic) writing systems as developed into Greek, Brahmic, Arabic and such writing systems first developed for writing Semitic languages, where consonants are most stable w.r.t. meaning-writing correspondence (i.e. various words connected to the concept "write"), and vowels are highly variable. Abjads without vowel notation are therefore very good for those languages. Vowel diacritics could be added as needed, and they were more needed in the languages written in Brahmic writing systems.

Historical conservatism explains the persistence of vowel-impoverished writing systems such as Brahmic writing, or Arabic script. Despite the rather vowel-dependent nature of non-Arabic languages written in Arabic script, as far as I know, Sorani Kurdish is the only language that has adopted it into an almost-alphabet. Old Persian cuneiform is semi-alphabetic, and it represents a somewhat different (and extinct) development of writing systems.

  • Didn't you know that Darwin refuted the idea that ontogeny recapitulates phylogeny? Mar 1 at 19:22

Even outside languages like Semitic where morphosyntactic features can often be used to correctly deduce the vowels in a word, vowels typically contribute much less to distinguishing words than consonants.

This is simply because languages almost universally have more consonants than vowels - often many more. The WALS chapter on consonant-vowel ratio says that the surveyed languages vary from a little over 1 (so only a few more consonants than vowels, as in Central Rotokas which, depending on analysis, may have as few as 6 consonants for 5 vowels), with 10 languages having ratios of 12 or more (the highest being Abkhaz at 29).

It's entirely expected then that specifying consonants will be prioritised over specifying vowels.

The fact that so many of the world's scripts developed from Ancient Egyptian hieroglyphs and more specifically the early Semitic abjads where vowels carry even less functional load has likely skewed the distribution a little, but is not the sole cause.

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    Not quite universally. As I just mentioned in Sir Cornflakes’ question on the matter Danish at least has more vowel phonemes than consonant phonemes – by some accounts a fair few more, even. Apr 21, 2023 at 11:18
  • @JanusBahsJacquet yep, looks like that's one of the cases WALS missed. Also as discussed in the comments on Draconis' answer it looks like several Lakes Plain languages also have more vowels than consonants
    – Tristan
    Apr 21, 2023 at 13:00
  • The English ratio is not far off 1 either. Apr 21, 2023 at 13:01
  • @JanusBahsJacquet of course the Danish writing system does not reflect this though, being almost identical to the far more consonant-based Bokmål Norwegian. Apr 21, 2023 at 14:09

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