Stress

In phonology, the term stress refers to an abstract property of syllables within the word domain. Stressed syllables are pronounced with more prominence than unstressed syllables. Prominence may involve greater amplitude, higher pitch, greater duration or greater accuracy of articulation (most notably in vowels).

Lexical stress may be distinctive, as in 'inCREASE' (verb) vs 'INcrease' (noun).

The term stress is also more generally used to indicate which words or phrases in a sentence bear accent (are in focus).

General rules of stress assignment in English
There is only one primary stress position per word. Only syllables with a vocalic nucleus may be stressed.

Rules of stress placement for nouns and verbs
There are several, partly competing rules of stress assignment in English. The rules are sentitive to at least four factors: (i) the lexical class of the relevant item, (ii) the number of syllables, (iii) the phonological make-up of each of the syllables involved, and (iv) the historical origin of the word.

Disyllabic nouns
are mostly stressed on the penultimate syllable: PRESent, EXport, CHIna, TAble; exceptions are found in recent loan words, e.g. poLICE, hoTEL.

Disyllabic verbs

 * ... are stressed on the ultimate syllable if it is heavy: carouse, esteem, fatigue, foment, maintain, etc.
 * ... are stressed on the penultimate syllable if the ultimate syllable is not heavy: ambush, banish, brevet, cancel, etc.

Trisyllabic nouns

 * ... are stressed on the penultimate syllable if it is not light: appendix, banana, intestine, etc.
 * ... are stressed on the antepenultimate syllable if the penultimate syllable is light: asterisk, citizen, cinema, etc.

Trisyllabic verbs

 * ... are stressed on the peunultimate syllable if the ultimate syllable is not heavy: abandon, accomplish, elicit, etc.
 * ... are stressed on the antepenultimate syllable if the ultimate syllable is heavy: analyze, celebtrate, culminate, etc.

Distinctive lexical stress
There are many disyllabic words in English whose meaning and class is distinguished by stress, e.g. present. If the word is stressed on the penultimate syllable, it functions as a noun (gift) or an adjective (antonym of absent); if the ultimate syllable is stressed, the word functions as a verb (offer). Similarly export, import, contract, object, etc.

Rules of stress placement for adjectives
Adjectives share properties with both verbs and nouns, as far as their prosodic behaviour is concerned. Many disyllabic adjectives are stressed on the penultimate syllable: ancient, fragile, hollow, narrow, etc. Often, the stress position within a disyllabic adjectives is a function of the final syllable or suffix. For example, adjectives ending in -ant, -ow, -ient and -ous are normally stressed on the penultimate syllable: flagrant, callow, ancient, anxious. Specific (mostly Latinate) suffixes attract stress, e.g. '-eme (extreme, supreme) and -ene (serene, obscene).

Stress in adjective-noun combinations
In cases of groups of two or more words, the place of stress depends on whether the group is a syntactic phrase or a compound noun. If it is a syntactic phrase, the adjective is usually less prominent while the noun carries the main stress: a nice GUY, a big HOUSE, a good IDEA. If two nouns form a compound noun, the stress is regularly put on the first word ('lefthand stress rule'): a HOT dog, a PICture frame. There are many (partly regular) exceptions to this rule, however, e.g. silk TIE and apple PIE (cf. Plag 2003).

Cases of stress variation among native speakers
In a few words, variation in stress assignment can be observed, which is partly conditioned by diatopic or diastratic variation, but which is sometimes also idiolectal. For example, some people say teleVIsion while others say TELevision. Another example is CONtroversy vs. conTROversy.

Literature

 * Burzio, Luigi (1994). Principles of English Stress. Cambridge: Cambridge University Press.
 * Carr, Philip (1999). English Phonetics and Phonology. Oxford: Blackwell.
 * König, E. and Volker Gast (2009). Understanding English-German Contrasts. 2nd ed. Berlin: Erich Schmidt (Ch. 3 on stress).
 * Giegerich, Heinz J. (1992). English Phonology. Cambridge: Cambridge University Press.
 * Plag, Ingo (2003). Word Formation. Cambridge: Cambridge University Press.