Language tip of the week: occur

In this weekly post, we bring more useful content from the Macmillan Dictionary to English language learners. These tips are based on areas of English which learners often find difficult, e.g. spelling, grammar, collocation, synonyms, etc.

This week some advice about the spelling of the word occur and other examples of words ending in -ur or -er:

Don’t write the -ed and -ing forms of occur with only one ‘r’. The correct spellings are occurred and occurring:
✗ It never ~~ocured~~ to me that I could be wrong.
✓ It never occurred to me that I could be wrong.
✗ Many changes are ~~occuring~~ at every level of education.
✓ Many changes are occurring at every level of education.

The reason why the ‘r’ is doubled in the -ed and –ing forms is that the stress falls on the final syllable of the verb in its infinitive form: occur.

The same rule applies to most other verbs ending in -ur and -er where the stress falls on the final syllable:

prefer preferred preferring

confer conferred conferring

concur concurred concurring

When the stress does not fall on the final syllable, the -ed and -ing forms are spelled with one ‘r’:

utter uttered uttering

cater catered catering

murmur murmured murmuring