Since stress can be realised through a wide range of phonetic properties, such as loudness, vowel length, and pitch (which are also used for other linguistic functions), it is difficult to define stress solely phonetically.
Stressed syllables are often perceived as being more forceful than non-stressed syllables.
In some languages, the placement of stress can be determined by rules. It is thus not a phonemic property of the word, because it can always be predicted by applying the rules.
Prosodic stress is also often used pragmatically to emphasize (focus attention on) particular words or the ideas associated with them. Doing this can change or clarify the meaning of a sentence; for example:
As in the examples above, stress is normally transcribed as italics in printed text or underlining in handwriting.
In English, stress is most dramatically realized on focused or accented words. For instance, consider the dialogue
The orthographies of some languages include devices for indicating the position of lexical stress. Some examples are listed below:
Though not part of normal orthography, a number of devices exist that are used by linguists and others to indicate the position of stress (and syllabification in some cases) when it is desirable to do so. Some of these are listed here.