Note: This post is NOT a duplicate of "is more commonly used" vs. "more common", which is focusing on the difference between "be more commonly used" and "be more common".

This post focuses on the difference between "is commonly used" and "sounds natural/is idiomatic".

As you may have noticed, I treated "sounds natural" and "is idiomatic" as the same. There are 3 pieces of consideration.

A nice answerer's opinion

First of all, non-native English speakers alway care about whether what they say sounds natural. So, lots of people ask whether some expressions are idiomatic. I also ask this kind of question a lot, such as Is it idiomatic to say "could only be used"? and the following.

An answer to the post Is it idiomatic to say "grammatical and idiomatic"? says

... it is both grammatical and idiomatic in the sense that it sounds natural, but it is not really what you could call a "commonly used" phrase.

which conveys, I suppose, that some expressions sounds natural are usually idiomatic.

Google Ngram

I put a group of phrases on Google Ngram and got this.

enter image description here

Which illustrates clearly that "sounds natural" and "is idiomatic" have almost the same points.

Cambridge Dictionary

Cambridge Dictionary gives this definition about "idiomatic"

containing expressions that are natural and correct

Obviously, idiomatic and natural are synonyms each other.

Commonly used

The last and the most difficult part is the difference between "is commonly used" and "sounds natural/is idiomatic".

The part that I quoted earlier also implies that, some expressions sounds natural are not really "commonly used". For example, "grammatical and idiomatic" might sounds natural but it is not really "commonly used".

The Google Ngram also suggests that "commonly used" is really commonly used than "sounds natural/is idiomatic".


Why is that? Could someone explain a bit more? Could someone name more examples where some expression sounds natural are not "commonly used"?

  • 3
    I think you're making too much of the Ngram results. Ngram will tell you how common a phrase is, but it won't tell you what the meaning is in context for any of those uses. "Is common" is itself a very common phrase that could refer to all kinds of things, not just wording.
    – Kyralessa
    Mar 12, 2020 at 13:10
  • 3
    How often does the average person talk about grammar in everyday life? "Grammatical and idiomatic" may well be a natural expression to use when you are discussing grammar, but it's hardly 'commonly used' Mar 12, 2020 at 13:18
  • Something being less common than a very common phrase in English doesn't make it not common.
    – Sparksbet
    Mar 12, 2020 at 13:51

1 Answer 1


TL;DR: Don't use Google ngrams for this sort of analysis.

You need to understand what Google ngrams is doing. It helps to view the books the results have been found in:

  • sounds natural

    1. The natural and universal principles of harmony and modulation

      Tabular view of all sounds, natural and chromatic, in the modes of C major and C minor.

    2. Sounds and Society: Themes in the Sociology of Music

      Just as the diatonic scale sounds natural to western ears, so there is a belief in western societies that human beings are naturally competitive and acquisitive.

    3. Everglades National Park (N.P.), Tamiami Trail ...

      The natural ambient soundscape is the aggregate of all the natural sounds that occur in park units, together with the physical capacity for transmitting natural sounds. Natural sounds occur within and beyond the range of sounds that humans ...

    4. Yellowstone and Grand Teton National Parks (N.P.), Winter ...

      ... for transmitting natural sounds. Natural sounds occur within and beyond the range of sounds that humans can perceive and can be transmitted through air, water, or solid materials.

    5. Merced Wild and Scenic River: Chapter 9

      The desired sounds during these times are referred to as natural quiet, a term used to describe ambient (outdoor) natural sounds without intrusion of human-caused sounds. Natural quiet can be essential for some individuals to achieve a ...

    6. Management Policies 2001

      The natural soundscape is the aggregate of all the natural sounds that occur in parks, together with the physical capacity for transmitting natural sounds. Natural sounds occur within and beyond the range of sounds that humans can perceive, ...

    7. An Introduction to Language

      Choose the Sounds Natural class [m p w] [h v θ ] [n l j a] [i u e] [t l z] Sounds Natural class [d b k] [ ŋ k] [a. smallest possible subclass (e.g. for [d b ɡ] “obstruent” is accurate, but not as specific as “voiced stops”).

    8. Pumpkins and Petunias: Things for Children to Do in Gardens

      Let the children determine whether the sounds were natural or made by people. 7. As a group, fill out the following table. Sounds in the Garden Sounds Natural Sounds Man-made Sounds

    9. Natural Language Information Retrieval

      Conceptually, it sounds natural to any English native speakers that these words can be used to describe any finance-related topics, not necessarily limited to the legal topic “State Tax”.

    10. The Bloomsbury Companion to Phonetics

      Freeware such as PRAAT (Boersma & Weenink, 2011) allows researchers to manipulate aspects of a natural speech signal such as duration, formant transitions or the pitch contour, and resynthesize the signal so that it still sounds natural.

We're only interested in results where the topic is language and "sounds" is a verb:

  1. Music: noun
  2. Music: verb
  3. Nature: noun
  4. Nature: noun
  5. Artificial sounds: noun
  6. Nature: noun
  7. Language: adjectival
  8. Gardens: adjectival
  9. Language: verb
  10. Speech synthesis: verb

Only one of the first ten results is what we're looking for.

  • is idiomatic

    1. Collocational and Idiomatic Aspects of Composite Predicates ...

      ... where the idiomatic meaning is not distributed over the parts (such as saw logs = 'snore'), and “idiomatic combinations”, where, although the phrase is idiomatic in meaning, the parts carry identifiable portions of that idiomatic meaning (such ...

    2. Writing Idiomatic Python 3.3
      [phrase not in preview]
    3. Idiomatic Creativity: A Cognitive-linguistic Model of ...

      The expression is idiomatic on all counts: the selection of ...

    4. Creative Compounding in English: The Semantics of ...

      Kooij argues his point by claiming very rightly that sweetheart is idiomatic compared to sweetmeat, but sweetmeat is more idiomatic than sweet corn.

    5. A Practical System of Rhetoric, Or, the Principles and Rules ...

      It is sometimes said of a style, that it is IDIOMATIC AND EASY. These epithets are generally found in connexion, and where the former is justly applied, the latter denotes a natural consequence. A style which is idiomatic, will appear to have ...

    6. A Dictionary of Modern English Usage: The Classic First Edition

      “Idiom " is the sum total of such forms of expression, & is consequently the same as natural or racy or unaffected English ; that is idiomatic which it is natural for a normal Englishman to say or write; to suppose that grammatical English is either ...

    7. Writing Idiomatic Python 2.7.3
      [phrase not in preview]
    8. Emerging Bilingual Speech: From Monolingualism to Code-Copying

      For instance, the following two particle verbs have the same particle and both main verbs express movement: alla käima “to deteriorate” is idiomatic (down + to go), whereas alla kukkuma “to fall down” (down + to fall) is not.

    9. Idioms: Processing, Structure, and Interpretation

      A simple litmus, though not an infallible one, for whether a sense is idiomatic is to consider its expression in another language.

    10. This Is Not a President: Sense, Nonsense, and the American ...

      This increment of “more” and “better” is idiomatic in our excremental culture.

We're only interested in results where the topic is language:

  1. Language
  2. Programming
  3. Language
  4. Language
  5. Language
  6. Language
  7. Programming
  8. Language
  9. Language
  10. Language

Eight of the first ten results are what we're looking for.

  • is common

    1. Intellectual Property is Common Property: Arguments for the ...

      It is common that they talk about inspiration on which they depend and that one has to wait until it arrives.

    2. Cryptosporidium is Common in Dairy Calves: National Dairy ...
      [no preview]
    3. Common Sense: The Foundations for Social Science

      It is therefore important to ask: under what conditions is common sense likely to develop and under what conditions is it endangered?

    4. What is Common Sense?
      [no preview]
    5. Thomas Aquinas on Human Nature: A Philosophical Study of ...

      In other words, the common sense is not common in the way that a universal is common, being predicated of (or even belonging to) each particular thing.

    6. Handbook to the Book of Common Prayer

      This is dependent upon the first: if it is common there must be forms, 'for common sense almost will tell us that when many are to pray together as one man, if their thoughts are to go together, they must agree beforehand what is to be the ...

    7. Shakespeare's Common Prayers: The Book of Common Prayer and ...

      “'Tis not alone my inky cloak,” he notes, for he is wearing black, and “I have that within which passeth show.” But his immediate response, in the moment of exchange, is a formal repetition. “Ay, madam, it is common,” he answers

    8. Common Perioperative Problems and the Anaesthetist

      Hyperkalaemia is common in patients with renal failure because of reduced ability to excrete a given potassium load, although it is more common in patients with oliguric renal failure than in those with non-oliguric failure.

    9. Atlas of Common Pain Syndromes E-Book

      Sleep disturbance is common.

    10. Aboriginal Customary Law: A Source of Common Law Title to Land

      It is common law because it is not statute law; it is local law because it is the law of a particular place as distinguished from the general common law.

We're only interested in results where the topic is language:

  1. Intellectual Property
  2. Animal Husbandry
  3. Common Sense
  4. Common Sense
  5. Philosophy
  6. Prayer
  7. Literary Analysis
  8. Medicine
  9. Health
  10. Aboriginal Customary Law

None of the first ten results is what we're looking for.

  • is commonly used

    1. Paediatric Cardiology

      ... less fibrosis than polygalactic acid. as a result, it is commonly used for surgery of the airway.

    2. Pediatric Cardiology for Practitioners E-Book

      This type of pacemaker is commonly used as emergency pacing.

    3. Weld Like a Pro: Beginning to Advanced Techniques

      A number of stainless steels are available, but 18-percent chrome and 8-percent nickel is commonly used for automotive applications.

    4. Fanaroff and Martin's Neonatal-Perinatal Medicine E-Book

      Inotrope therapy is commonly used for short-term dysfunction, especially in the immediate postoperative period.

    5. Manufacturing Processes - I

      ... is commonly used in conjunction with organic materials.

    6. Beyond Databases, Architectures and Structures. Paving the ...

      This indicator is commonly used to determine the trend's direction and strength.

    7. Pediatric Dermatology E-Book

      It is commonly used as a firststage procedure when a congenital nevus is too large to allow for complete excision in one procedure.

    8. Mosby's Review Questions for the National Board Dental ...

      ANS: A Dextromethorphan (A), an opioid-like compound, is commonly used as an antitussive; it is the “DM” found in cough syrups.

    9. New Technologies for Rural Development Having Potential of ...

      The other advantage is over rebuilding, a practice that is commonly used by farmers to overcome ...

    10. Comprehensive Biomaterials

      Nylon is commonly used as the outer layer of balloon angioplasty catheters and also as the balloon used for deployment of a stent or the expansion of an occluded artery.

We're only interested in results where the topic is language:

  1. Surgery
  2. Surgery
  3. Welding
  4. Medicine
  5. Manufacturing
  6. Computer Science
  7. Paediatric Dermatology
  8. Dental Hygiene
  9. Rural Development
  10. Surgery

None of the first ten results is what we're looking for.

So, the results for the first ten hits on Google Books about language for each phrase are:

  • 1 / 10: sounds natural
  • 8 / 10: is idiomatic
  • 0 / 10: is common
  • 0 / 10: is commonly used

This shows that Google ngrams is the wrong tool to use for this analysis. It also shows how common "is common" and "is commonly used" are in general English. Only "is idiomatic" is narrow enough to be mostly about (natural) language. Without a tool that can show results only from the correct context, your question is unanswerable.

  • Despite being the longest answer I've ever seen, it doesn't actually answer the question.
    – Lambie
    Jun 21, 2020 at 15:13
  • @Lambie I'm not sure the OP knew exactly what they wanted to ask. They had attempted to do some research on their own and I pointed out the flaw in their methodology. I'm also not sure that this is a question specifically about English. How would the answer change if it was about French? It seems more about concepts than English. The words to describe the concepts would change, but not the concepts themselves. The OP apparently liked my answer because they accepted it. If you point out something I failed to address specifically and I agree with you, I will update my answer if I can.
    – CJ Dennis
    Jun 23, 2020 at 2:54
  • A small pool of samples can be biased. Maybe you need some NLP algorithm to do a big data analysis. lol
    – Michael
    Dec 13, 2022 at 15:11

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