This paper presents a study on the automatic detection of prosodic prominence in continuous speech, with particular reference to American English, but with good prospects of application to other languages. Perceptual prosodic prominence is supported by two different prosodic features: pitch accent and stress. Pitch accent is acoustically connected with fundamental frequency (F0) movements and overall syllable energy, whereas stress exhibits a strong correlation with syllable nuclei duration and mid-to-high-frequency emphasis. This paper shows that a careful measurement of these acoustic parameters, as well as the identification of their connection to prosodic phenomena, makes it possible to build automatic systems capable of identifying prominent syllables in utterances with performance comparable with the inter-human agreement reported in the literature without using any kind of information apart the acoustic parameters derived directly from speech waveforms.