Stress and Vowel Reduction in English - Lexical and Prosodic Stress

Lexical and Prosodic Stress

Lexical stress (word stress) is regarded as being phonemic in English; the position of the stress is generally unpredictable and can serve to distinguish words. For example, the words insight and incite are distinguished in pronunciation only by the fact that the stress is placed on the first syllable in the former word, and on the second syllable in the latter. Similarly, the noun and the verb increase are distinguished by the placement of the stress in the same way – this is an example of an initial-stress-derived noun.

Some words are shown in dictionaries as having two levels of stress: primary and secondary. For example, the RP pronunciation of organization may be given as /ˌɔːɡənaɪˈzeɪʃən/, with primary stress on the fourth syllable, secondary stress on the first syllable, and the remaining syllables unstressed. For different ways of analysing levels of stress in English, see Degrees of lexical stress below.

English also has relatively strong prosodic stress, whereby particular words within a phrase or sentence are given additional stress in order to place emphasis on the information that they convey. There is also said to be a natural "tonic stress" which falls on the last stressed syllable of a prosodic unit – for more on this, see below under Descriptions with only one level of stress.

English is classed as a stress-timed language, which means that there is a tendency to speak so that the stressed syllables come at roughly equal intervals. See Isochrony.