I'd like to know if there is a grammar rule stating when the last consonant of the verb has to be doubled. E.g. why: "to cut" -> cutter, "to program" -> programmer, but "to read" -> reader?

  • I personally have not come across any written rules regarding these word forms. – Eniola Apr 28 '17 at 16:19
  • you double to prevent an unintended pronunciation. Cuter rhymes with pewter. Programer would rhyme with “pro gamer” etc. – Jim Apr 28 '17 at 16:43
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    I don't think this is a "grammar rule," more of a spelling or orthography rule. – RaceYouAnytime Apr 28 '17 at 18:24
  • The word was programme until the Americans shortened it. So clearly, the noun has to be programmer. – Peter Shor Apr 28 '17 at 19:54

The general rule is: double a single consonant letter following a single vowel letter with a short vowel sound; don't double anything else. (The doubled consonant is a cue that the vowel sound should remain short.)


  • cut has a short 'u' and a single 't': therefore cutter.
  • program has a short 'a' and a single 'm': programmer.
  • read has a long 'e' sound from 'ea': reader
  • head has a short 'e' sound but it comes from a double-vowel 'ea', so header.

Of course, this being English, there will be exceptions.

| improve this answer | |
  • If you added letter after consonant and vowel to parallel short vowel sound, the answer would be perfect. I recommend this because orthographic rules often conflate letters and sounds; they should be distinguished when stating the rules carefully. Since there are only 5 vowel letters to represent at least 14 vowel sounds in English, this is one of the dodges to make the vowel letters do double duty. – John Lawler Apr 28 '17 at 22:12
  • @JohnLawler tweaked as indicated. :-) – Hellion Apr 29 '17 at 4:41
  • Another important point to note is probably stress: the "short vowel sound" doubling rule doesn't apply with words like "edit, edited, editing" where the "i" corresponds to an unstressed vowel. – herisson Apr 29 '17 at 5:09

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