Ask a linguist: experts answer your questions: "What exactly is contrastive stress in English?”

It is not what you say but how you say it. In spoken English, the intonation contours of an utterance (also called prosody) can greatly affect the meaning that the speaker conveys. Contrastive stress is often described as the most conspicuous and ubiquitous prosodic phenomenon in English (you may also see it called contrastive focus, contrastive accent or prosodic contrastive focus). Contrastive stress is used to draw the addressee’s attention to a particular constituent in an utterance – one that is not typically accented – and, in doing so, it triggers a particular interpretation of the utterance. Its acoustic salience or extra ‘oomph’ is characterised by greater auditory prominence and articulatory care, loudness, and increased intensity.