In case anyone wants to take issue with the way I spelled "traveled" in a recent post, here's the rule I learned in elementary school (don't ask me how I remember it) about doubling the final consonant of a word before adding a suffix: Â If the consonant is single, and the emphasis is on the last syllable, AND the quality of the last syllable is "long", the consonant is doubled before adding a suffix; not otherwise.
The long vowels are found in "heat", "hate", "hope", "foot", "hoot" and, I think, "hawk". Â The short vowels are "hit", "pet", "hat", "hot" and "hut". Â The twelfth English vowel, schwa is short, but doesn't come in for doubling because by definition it never has the emphasis.
Some examples:
"Hot" becomes "hotter" because the emphasis is on the ultimate syllable (its only syllable is the last one, of course) and the vowel is short. Â Likewise "besotted".
"Market" isn't doubled, even though the ultimate syllable is short, because the emphasis is on the penult: "marketed", "marketing". Â Likewise "customize", "bedeviled" and "opening".
"Touch" emphasizes the ultimate and the vowel is short, but it isn't doubled (to something like "touchhing" or "touchched") because it ends in multiple consonants. Â Likewise "hacking", "crutched", "commander" etc.
"Rude" becomes "ruder", not doubled, because even though the emphasis is on the ultimate, the vowel is long. Â Likewise "eloping".
This leads to some disagreement with the standard dictionaries. Â They think I should write "travelled", Â for example, and some of them also "cancelled", though I insist on spelling them with an undoubled 'l' because the emphasis is on the penult. Â They also want me to write "controlled", while I stick to "controled" because the final syllable is long. Â (I suppose phoneticians could argue that the 'o' that comes before 'l' is modified and no longer truly long; I can't feel it.)
And then there's "kidnapped". Â I spell it with a doubled 'p' despite the fact that the emphasis is on the penult; I just can't bring myself to write "kidnaped". Â I comfort myself with the thought "kidnap" is actually a compound word, that "nap" is actually the root. Â It may even be true.