I would like to know a clear rule about when should I use double consonant.

For example: intelligent (yes), little (yes), collapse (yes), elegant (no).

Not just about double l, but in general, is there any rule for double consonants?

  • Unfortunately, there is no clear answer. However, I wrote an answer to a similar question on ELU that I hope will be somewhat helpful: Rules for spelling double consonants in roots of words Etymologically, intelligent has the prefix inter- which assimilates to intel- before the consonant l.
    – sumelic
    Jul 28, 2016 at 21:18

2 Answers 2


There are some languages that have very clear, consistent rules about how words are spelled, and how that spelling translates into pronunciation. Unfortunately, English is not one of those languages.

English started as a Germanic language, but was then heavily influenced by French (and thus Latin), apparently due to the Norman Conquests. Since then, a variety of other languages have had varying degrees of influence on English. Thus, English is a mixture of many different standards, making it inconsistent.


That's vocabulary. There are no rules for that.

When you double consonants, it applies in general for -ing forms, comparative & superlative adjectives & past simple with regular verb forms.

It's like asking: why travelling and not traveling? Because BrE use the former and AmE the latter. It's just vocabulary.

  • I never thought about the BRE and AME situations (thanks), how each one deals with the double consonant.. but for example.. you mean.. it's ok to use "perfectly" and "perfectlly"?
    – ivanleoncz
    Jun 9, 2016 at 3:08
  • That's different: perfectly is correct, the one with double l not. Sometimes, when constructing adverbs, you get to have a doble l. For instance, careful - carefully
    – Schwale
    Jun 9, 2016 at 3:12
  • 1
    I can't think of an example where double L would be added to a word that originally had no L's.
    – nnnnnn
    Jun 9, 2016 at 3:53
  • 1
    The AmE rule is if the emphasis is on the last syllable, you double the consonant: rappel => rappelling vs travel => traveling. Also, for single syllable words ending in a consonant, you would double: put => putting, let => letting. Jun 9, 2016 at 7:09
  • @MrWonderful Makes much more sense now (thanks). Is it possible to have special cases like "intelligent"?
    – ivanleoncz
    Jun 9, 2016 at 13:59

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