Is it unparallelled or unparalleled?

When adding -ing and -ed to verbs, we sometimes double the consonant beforehand. People are often confused with ‘unparallelled/unparalleled’, ‘benefitted/benefited’, ‘focussed/focused’ and ‘targetted/targeted’. This tip answers some of those queries.

The official requirements are that we ‘double a single consonant letter at the end of any base where the preceding vowel is spelled with a single letter and stressed’.

What does this mean in practice?

Examples:

word present participle past participle
bar barring barred
beg begging begged
occur occurring occurred
permit permitting permitted
patrol patrolling patrolled

It is true to say that there is usually no doubling when the preceding vowel is unstressed (‘enter’ becomes ‘entering/entered’; ‘visit’ becomes ‘visiting/visited’) or when the preceding vowel is written with two letters (‘tread’ becomes ‘treading/treaded’).

Unparallelled

American British English
parallel parallel
paralleling parallelling
paralleled parallelled

Example:

The vetting service from Future Perfect is unparallelled.

Others in this grammatical group (verbs ending in an unstressed vowel, followed by the letter ‘l’) are ‘cancel’, ‘counsel’, ‘dial’, ‘model’, ‘travel’ and ‘signal’.

Some words change their spelling to cope (they add a letter ‘k’).

word present participle past participle
panic panicking panicked
traffic trafficking trafficked
frolic frolicking frolicked
bivouac bivouacking bivouacked

What about ‘focus’?

This word can take either double or single s, with the single option being highly preferred.

word present participle past participle
focus focusing/focussing focused/focussed