In linguistics, stress is the emphasis given to some syllables (often no more than one in each word, but in many languages, long words have a secondary stress a few syllables away from the primary stress, as in the words cóunterfòil or còunterintélligence.

The way stress manifests itself in the speech stream is highly language-dependent. In some languages, stressed syllables have a higher pitch than non-stressed syllables — so-called pitch accent (or musical accent). There are also the following types of accents: force accent (also known as dynamic accent), quantitative accent , qualitative accent .

English is a so-called stress-timed language, ie. stressed syllables appear at a roughly constant rate, and non-stressed syllables are shortened to accommodate this. Stressed syllables in English also have higher pitch than unstressed ones.

Stressed syllables are often perceived as more forceful or louder than non-stressed syllables. Research has shown, however, that vocal stress does not imply louder phonation, nor more forceful articulatory gestures.

Some languages have fixed stress, ie. stress is placed always on a given syllable, as in French (where words are always stressed in the last syllable), Finnish (stress always on the first syllable) or Quechua and Esperanto (always on the penultima -- the syllable before the last one). Other languages have stress placed on different syllables in a predictable way (they're said to have a regular stress rule), such as Latin.

There are also languages like English or Spanish, where stress is unpredictable and arbitrary, being lexical; that is, it comes as part of the word and must be learned with it. In this kind of language two words can differ only by the position of the stress, and therefore it's possible to use stress as a derivative or inflectional device. English shows this with noun/verb pairs such as to record ("to register, to inscribe") vs. a record ("a register, an entry"), where the verb is stressed on the last syllable and the corresponding noun is stressed on the first. Further, many words have different stresses in British English and American English.

In Romance languages, stress takes part in the verb conjugation and it produces an interesting phenomenon by which the vowels /e/ and /o/ in the root of some verbs become diphthongs when stressed. For example, in Spanish the verb volver has the forms volví, volviste, volvió in the past, and vuelvo, vuelves, vuelve in the present. In these Spanish verbs, stressed /o/ becomes /ue/ and stressed /e/ becomes /ie/ (Italian has /o/ → /uo/ instead).

Stress in poetry

Poetry in English depends upon stress to establish the meter of the poem. Stress is usually thought of as strong or weak. Some people distinguish a third, intermediate stress level.

For example: in the word reconsider, the stress pattern is _'recon'sider (intermediate - weak - strong - weak).

See also

• Phonology
• Syllable
• Pitch accent
• Timing
• Initial-stress-derived noun