I was a little surprised to find that the PIE root of do and δίδωμι is *deh₃-, not *do-. How did we get the "o" vowel sound from eh₃? I don't actually know how to pronounce h₃, but I'm assuming that *deh₃- rhymes with "meh"... correct me if I am wrong here.

This question popped up when I was looking up "anecdote" in a dictionary and reading its etymology. I saw that the word derives from ἐκ + δίδωμι (to give out, publish). The familiar root "do" is present. But when I looked up the origins of "do", I found *deh₃-.

(There you have it: an anecdote about anecdote.)

I might as well include a guess. My guess is this. *deh₃- became *di-deh₃-, but *di-do was considered a euphonic improvement somewhere down the line, hence δίδωμι. And, as Wiktionary suggests, the reduplication was lost in Latin, giving do.

  • 2
    If you make your anecdotes any more meta, they have to be taken to the meta site. Seriously, though, the question is interesting! But you should not be fooled by the first person singular ending -o; the Latin stem seems to be da-.
    – Joonas Ilmavirta
    Commented Apr 18, 2017 at 6:24
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    meh₃ does not necessarily rhyme with meh, in fact, nobody knows (so it might actually rhyme anyways !). h₃ is basically a hypothetical unknown phoneme that influences vowel quality in PIE. It explains a lot of exceptions to sound change laws from the reconstructed PIE language to the attested ancient IE languages. If you've got time to kill, you can read en.wikipedia.org/wiki/Laryngeal_theory
    – blagae
    Commented Apr 18, 2017 at 11:34

2 Answers 2


δίδωμι “I give” and δίδομεν “we give” can be explained either by “classic” (non-laryngeal) or “modern” (laryngeal) theory. The former derives the singular from full-grade *dō- and the plural from zero-grade *də- (with secondary ə>o by analogy). The latter posits full-grade *deh3- > dō- and zero-grade *dh3- > do; δίδωμι is then from *di-deh3-mi, and δίδομεν from *di-dh3-men.

By the way, you are not alone in not knowing how to pronounce h3. Nobody knows how it was pronounced. It is a quasi-algebraic symbol.

  • Thanks! This helps a lot. So the full grade of *deh3 is dō. It sounds like PIE roots often underwent full-grade vowel changes? Was there a tendency for vowels to either become full-grade or zero-grade?
    – ktm5124
    Commented Apr 18, 2017 at 19:22
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    @ktm5124, vowel grade variation (aka ablaut) was an integral part of PIE grammar, so there's no general answer to your question -- the grade depends on the specific grammatical form (and isn't always predictable even then). See en.wikipedia.org/wiki/Indo-European_ablaut
    – TKR
    Commented Apr 20, 2017 at 21:16

*h3 is called the "o-colouring laryngeal," which means that it "colours" (i.e., changes) a neighbouring e into *o or : the former from *h3o and the latter from *oh3. See *h3ewis > ovis and *deh3[r/n]m̥ > dōnum.

Now, when *hx (or any other laryngeal) is not next to an *e, then they yield other vowels: *a in Latin, *i in Sanskrit, and *e, *a or *o in Greek respectively for *h1, *h2 and *h3.

Rasmussen postulates *h1 to be the voiceless glottal fricative [h] (though some postulate it as the glottal stop [ʔ]) when acting as a consonant, and the unrounded central vowel [ə] when acting as the nucleus of a syllable; *h2 to be the voiceless velar fricative [x] (others postulating the pharyngeal approximant [ʕ] in a consonant role and the near open central vowel [ɐ] in a syllable nucleus; and finally *h3 to be the labialised velar fricative [ɣʷ] (though [xʷ] and [ʕʷ] also have adherents) in consonant mode and the rounded central vowel [ɵ] in a syllable nucleus.

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    Thanks for the explanation. Interesting to learn how the laryngeals affect their neighbors. I don't think I have seen you here before, so allow me to say, welcome to the site!
    – ktm5124
    Commented Apr 18, 2017 at 16:01

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