Question: “Dear Grammar Guy: I’ve noticed that words like ‘cancel’ and ‘travel’ only have one ‘L’ when the ‘-ed’ suffix is added to them, but other words like ‘stopped’ and ‘dropped’ double the final consonant for a suffix. How do you know when to do one, and when to do the other?”

Answer: Learning when to double the final consonant can be a tricky thing for non-native English speakers (and native speakers, too). Fortunately, there are a few general rules you can follow almost all of the time.

Rule No. 1: Double the final consonant in a one-syllable word that ends in a single consonant when adding a suffix that begins with a vowel. For example, “trap” becomes “trapping,” rather than “traping;” “bar” becomes “barring;” “sit” becomes “sitting;” etc.

An exception to this rule is one-syllable words with a long vowel sound (i.e. “sleep” becomes “sleeping,” rather than “sleepping.).

 Rule No. 2: In a multi-syllable word, double the final consonant if the last syllable is stressed. Examples include “referring,” “committed” and “admitting.” An exception is words where two vowels come before the final consonant, like “contain” or “bespeak.”

Rule No. 3: In American English, verbs ending in a vowel + “L” are not doubled when a suffix beginning with a vowel is added. Examples include “traveling,” “canceling,” “fueling,” “dueling,” etc. In British English, the “L” would be doubled.

Worth noting here: While a single “L” is the “American” spelling of words like “canceling,” the British version “cancelling” is still grammatically correct and acceptable. You will get flak from American editors about it, however.

This is a subject where there are more rules than I can cover in a single column. You probably learned most of them in school (words that end in “Y,” words that end in “E,” etc.), so hopefully these three rules augment the knowledge you already have. And if you really want to spell “canceled” the British way, I suppose it’s fine … although you may be stepping into an intercontinental grammar grudge match.