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# Hyphens are sometimes used in English to denote syllable breaks, particularly for prefixes, as when a (repeated) vowel is pronounced on its own rather than being silent or merged in a diphthong, as in 'shell-like' and 'anti-intellectual', where some other languages (and some English authorities) use a diaeresis like 'noël'. In British English, hyphens are also occasionally employed where readers would otherwise be tempted into a mispronunciation (e.g. co-worker is so punctuated partly to prevent the reader's eye being caught automatically by the word cow—though see also the following note on prefixes).
# Certain prefixes (co-, pre-, mid-, de-, non-, anti-, etc.) are often hyphenated, though usage varies between American and British English. British English tends towards hyphenation (pre-school, co-worker) whereas American English tends towards omission of the hyphen (preschool, coworker). A hyphen is mandatory when a prefix is applied to a proper (capitalized) adjective (un-American). The AP Stylebook provides further information on the use of "co-" as a prefix.