title_body: Naturalness of different universal quantifiers based on the size of the domain you're quantifying over
upvoted_answer: This is not inherently unnatural. As you point out, English &quot;both&quot; (and reasonable translations such as Spanish &quot;ambos&quot;) easily fit the role of every(2) (I would argue that whether the noun is marked as singular or plural isn't particularly interesting here).
  every(1) can be reasonably analyzed as a definiteness marking and is encompassed in most Indo-European languages by the definite article (&quot;the&quot;, &quot;el&quot;, &quot;i&quot;, το), as shown by the sentence &quot;The sun is shining.&quot; (This sentence can be used without explicitly introducing the sun into the conversation specifically because there is only one reasonable referent.)
  In particular, I could see one set of forms evolving from the definite articles in a language with heavy number marking (i.e. &quot;the (singular)&quot; becomes each(1), &quot;the (dual)&quot; becomes each(2), etc.).
  What I would be very surprised to see in a natural language is a fully consistent system of these, where each(), every(), and all() all cover the same numeric distinctions in the vein of the Esperanto correlatives.
  I would also be surprised to see more than a couple of these in any language that does not make at least as many number  distinctions elsewhere.