Stress is the relative prominence of a syllable in comparison with the other syllables in a given domain, typically a lexical word.

Phonetically speaking, stress is realised by changing the fundamental frequency (i.e. the pitch), the duration (i.e. the length) and the intensity (i.e. the volume) or any combination of these phonetic features. Thus stressed syllables receive greater prominence by means of pitch, duration and intensity. Research shows that in Spanish the most important correlate of word stress is pitch.

Functions of stress

Stress can have various linguistic functions. It helps group speech sounds into words. In languages like Spanish and English, stress has a distinctive function, that is, it differentiates word meanings: ESP ánimo ‘mood’, animo ‘I encourage’, animó ‘s/he encouraged’; ENG record  (verb), record (noun). In other languages stress might have a delimitative function, e.g. in Hungarian or Czech it always falls on the first syllable of the word which helps listeners to segment running speech into words.