In British English cancelled and travelled must be used when forming the Past Tenses or the Present Participles. Whereas American English have started to use canceled and traveled. The single consonant L has become very common in American English but it is not acceptable in British English. Below are a list of verbs with the double consonant.
Verbs ending with L:
- Label: labelled / labelling
- Quarrel: quarrelled / quarrelling
- Cancel: cancelled / cancelling
- Travel: travelled / travelling
In British English, verbs ending with the consonant L are not the only verbs that require a double consonant to form the Past Tenses and the Present Participle. There are also some verbs that end with T, P, R which require the doubled consonant also. For example:
Verbs ending with T:
- Fit: fitted / fitting
- Admit: admitted / admitting
- Commit: committed / committing
- Chat: chatted / chatting
Verbs ending with P:
- Chop: chopped / chopping
- Flip: flipped / flipping
- Snap: snapped / snapping
- Whip: whipped / whipping
Verbs ending with R:
- Recur: recurred / recurring
- Deter: deterred / deterring
- Spur: spurred / spurring
- Occur: occurred / occurring
