I would like to know which natural languages are grammatically the most regular and irregular. There are several titbit articles on the web but none are definitive or explanatory.

By regular, I want to mean that the are well-defined rules to derive words from root, and to make plurals, gender plays no role or has the well-defined way to determine gender, etc.


  • German is highly irregular in terms of pluralization than English. Kind-Kinder, Vater-Väter, das Mädchen-die Mädchen
  • Gender is a headache in German, Spanish, Hindi etc. but not in English because except from changing he to she, there is no role of gender in forming sentence.
  • English, although less than German, is fairly irregular in word formation such as good-better-best, go-goes-went, eat-eats-ate etc.

I heard Turkish is somewhat regular, but I have no knowledge about how. I also don't know if there are many languages more regular than Turkish or not.

Can you please elaborate?

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    Just to make it explicit, the question is focused on morphological regularity, right? Commented Feb 28, 2016 at 21:21
  • 2
    I guess any totally isolating language would have to be considered completely regular? Keo (Austronesian, Indonesia) appears to have no morphology whatsoever, so has no irregularities. Commented Aug 11, 2023 at 23:25
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    @GastonÜmlaut I don’t know a thing about Keo, but Mandarin, which is also totally isolating (with the exception of three cranberry morphemes that can be considered suffixes addable to nouns, one of them also to pronouns), does still have a few cases of, if not morphological, then at least inflection-like irregularities; e.g., verbs (including adjectives) are negated using 不 , except the existential/possessive verb 有 yǒu, which uses 没 méi instead, and which can itself be suppressed when negated. Commented Aug 12, 2023 at 23:11

3 Answers 3


We have no quantitative metric of irregularity so the best you can hope for are ballpark figures. Also, your conception of regularity (which includes complexity) doesn't exactly match the concept of regularity used in linguistics – Classical Arabic verb conjugation is very complex, but not very irregular in the technical sense. In constructing a word in any language, the typical linguistic analysis is to discern a "base form" for the involved morphemes, which allows you to write rules generating all of the related word forms. That base form is not always some actual word of the language, thus the base form for the verb "be" in Classical Arabic is /kwn/, and kwn is not a possible word of Arabic. There are many regular but complex rules involved in getting a particular word form in Arabic. Given the linguist's viewpoint on regularity, having many rules does not create irregularity: rather, you have irregularity when formatives have to be arbitrarily (lexically) flagged as triggering or not triggering some process.

Again assuming the standard linguistic understanding of regularity / lexicality and the derivation of morphologically complex forms, it would be right to say that gender (be it animacy, sex, or noun-class type) constitutes a kind of irregularity. However, from the popular perspective "learn a word, and heuristically generate related forms based on that", gender is a headache in Germanic but not Spanish, since in learning the citation form of the noun, you can discern the gender most of the time (the real irregularities aren't enough to cause a headache). In some Bantu languages, the difference on this front between linguist's irregularity and popular irregularity is even more striking, since there are over a half-dozen pattern-classes that you just have to learn – but, when you learn the singular (e.g. in Kikuyu) the gender of the noun becomes obvious, since like with Spanish, the basic form of the word that you learn includes the arbitrary gender morpheme that you just have to memorize.

That said, Vietnamese would come in on the most-regular end of the scale, since there are apparently no irregularities or changes in form, whereas there are some idiosyncratic consonant insertions / deletions in Turkish inflection. Dinka comes in on the least-regular end of the scale. Formation of noun plurals is extremely chaotic and arbitrary, and you effectively have to learn singular and plurals. Apparently, outside of a certain core of vocabulary, speakers don't widely agree on singular and plural forms.

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    Quechua is another language with (if I'm not mistaken) no morphological irregularity at all. Finnish comes pretty close. On the whole agglutinative languages tend to be more regular than synthetic ones, it seems.
    – TKR
    Commented Feb 28, 2016 at 1:07
  • There are some lexical exceptions and non-productive gradation patterns (auto does not undergo gradation, paras inflects irregularly), but Finnish is pretty regular as long as you set up the right underlying forms, analogous to how Arabic is pretty regular. I think that Imbabura Quechua is the "most regular" of the Quechua languages, and it does have a fair amount of inflectional irregularity in verbs -- though it's not root-governed (e.g. 1st person /ni/ → [n] in the plural; 3rd person /n/ → Ø in the past). It depends on what counts as an "irregularity".
    – user6726
    Commented Feb 28, 2016 at 1:35
  • Hi, I have slightly changed the question, see edit log. Comment if it still makes no sense.
    – MAKZ
    Commented Feb 28, 2016 at 4:16
  • @TKR Well, that's part of what distinguishes agglutinative from fusional. Commented Aug 12, 2023 at 20:28

It depends on how much analogy occurs in the language. Sound change will always cause irregularities, but analogy will level it back out. So languages with a lower rate of sound change might have less irregularity, and languages with more sound change or less analogy might have more.

Navajo has very irregular verb forms.

Turkish is famously regular. As for the -de vs. -da thing, vowel harmony is entirely ─ and easily ─ predictable, and shouldn't be considered "irregularity."

Indonesian has very little morphology, from what I've seen, and what I've read has been entirely regular, as far as I know.

Irish is very irregular, having dozens of ways to form the plural, which are difficult to predict; same for the genitive. And gender is very hard to predict.

That's all I can think of off the top of my head. I hope it helps!

  • Various Austronesian languages have plenty of irregularity; Fijian, for instance, has a set of transitivity markers with many variants that can't be predicted.
    – jlawler
    Commented Aug 19, 2023 at 22:09

In answer to the question about Turkish, I would definitely say Standard Modern Turkish is extremely regular. For instance, virtually all Turkish verbs are regular in their conjugations. There are said to be only 15 irregular verbs in Turkish. But most of these are words seldom used. For instance, the word "to herd," as in "I am herding the sheep tomorrow." That is irregular, but if you are visiting Turkey, or living in a city for a while, you probably will not even use that verb.

Turkish is agglutinative. But regularity persists for all the suffixes. There is one thing very odd about Turkish, at least it will seem odd to anyone who is not Turkish. This is something called "vowel harmony." Vowel harmony may seem at first irregular, but it is not. Vowels in word suffixes change to make them harmonize with vowels in the preceding noun. (As far as I know, there is no other language in the world that has this feature of vowel harmony, unless it is one Amerindian language, called Guarani).

Here's a simple example.

The word "ev" means house. If you want say "at the house," you say,

evde. "de" means at, and it comes after the noun "ev."

Here's where the vowel harmony comes in.

Kapı means "door". Now if it's regular, you might think that "at the door" would be

Kapıde. That's not correct. The correct form is:

Kapıda. So both "de" and "da" mean "at". Again, this may seem irregular. But notice that the "a" at the end is "harmonized" with the "a" in the beginning of the word. Kapı has an "a" at the beginning, so the vowel in the suffix "da" matches or harmonizes with that first "a"

This might seem complicated at first. But the rule is "always vowel harmony," with no exceptions. For Turks, and for new learners, the sound, the harmonization of those two vowels just sounds better. As the musical note "F," if followed by G (rather than G sharp), just sounds better.

So what I have said above more or less covers the issue of regularity versus irregularity. As in English, words do not have genders, as they do in French and Spanish. Pronunciation is always regular and corresponds to the Roman alphabet (Turks gave up using Arabic script about a century ago). Plurals are regular, thought they do still have vowel harmony.

So "House" (ev) + plural marker is evler, while for "door" + plural marker is Kapılar. "e" matches "e" and "a" matches "a." There are no articles in Turkish, such as "some," "a" or "the."

So, the questioner wanted to know, and I quote, "By regular, I want to mean that there are well-defined rules to derive words from root, and to make plurals, gender plays no role or has the well-defined way to determine gender, etc."

Turkish has all that, and more. (I agree with poster who spoke about Spanish, in that Spanish is not so bad with gender as you might think: ending in "o" almost always is male, while "a" almost always is female. But Turkish is easier still on the "gender" question.)

With regard to pronouns, Turkish is like Chinese, in that there is one genderless pronoun, "O," which can mean "he" or "she." which is neither male, female or neuter. Turkish "O" can roughly corresponds with "it," though it can be used for people as well as things.

Turkish is made easier by the fact that it has no large consonant clusters, as Russian and Georgian do. It has no "tones", as Chinese does.

Something else that is interesting about Turkish is the way the word "God" operates. Turks use the Arabic word "Allah" to denote the one supreme Deity. But, unlike in Arabic, they have another name for god which comes from the Turk's distant pagan past. This is "Tanrı" which means god in the sense of one of the pagan gods, or just "gods" generally. If they want to say, O my God, they say, "Allahalahalah", slowly. But they might also say "Tanrı!" or "Tanrım," (My God!) Arabs literally say, "There is no God but God." (They do not say, "there is no God but Allah.)".

Turkish has borrowed many words from Arabic and Persian, but not so many from Latin, which has come to them through France, Italy, England and the US. (They have borrowed virtually nothing from Greek, not even place names, which they "Turkify." Instead of "Smyrna," the Greek name for that East Aegean city, the Turks say, "Izmir." (Aegean in Turkish is "Ege.)

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    "(As far as I know, there is no other language in the world that has this feature of vowel harmony, unless it is one Amerindian language, called Guarani.)" ─ This is wrong. To name a few: Mongolian, Kazakh, Azerbaijani, Finnish. Middle Korean had it, but it's starting to be lost. I believe it's also found in Tatar. Commented Aug 12, 2023 at 20:27
  • Indeed vowel harmony is a feature of Turkic, Mongolic and Uralic languages in general, part of what motivated lumping these families into (Ural-)Altaic. Commented Aug 18, 2023 at 14:40

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