Doubled letters

Consonant doubling is the biggest English spelling problem

     It causes more spelling errors than any other spelling difficulty.
     In root words of more than one syllable it is totally unpredictable.

Doubling a consonant is supposed to show that a vowel is short rather than long, as in

                     bitter – biter,  teddy –  tedious,  tinny – tiny

It was intended to apply just to stressed vowels. This is meant to explain why   ‘conferred’ and ‘committed’ have rr and ttin the past tense, but entered’ and ‘plummeted’ don’t (when –ed is added to ‘confer, commitenter’ and ‘plummet’).


Unfortunately, English consonant doubling is used very inconsistently. There is no reliable rule for deciding whether to double a consonant, or not, in similarly sounding words. Learners have to memorise, word by word, when to double and when not to, as the chart below summarises.


This rote-learning burden of 913 words defeats many learners.

Another 73 words exacerbate it even further.

49 words have unpredictable final -ff, -ll and –ss (if – stiff, stole – poll,  bus – fuss)
24 words don’t follow the –ccle patternof endings like apple,  bubble, tussle,
for example, chapel, double,  rustle.

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