Speech has rhythmic properties that widely differ across languages. When we listen to foreign languages, we may perceive them to be more musical, or rather more rap-like than our own. Even if we are unaware of it, the rhythm and melody of language, i.e. prosody, reflects its linguistic structure. On the one hand, prosody emphasizes content words and new information with stress and accents. On the other hand, it is aligned to phrase edges, marking them with boundary tones. Prosody hence helps the listener to focus on important words and to chunk sentences into phrases, and phrases into words. In fact, prosody is even used predictively, for instance to time the onset of the next word, the next piece of new information, or the total remaining length of the utterance, so the listener can seamlessly start their own speaking turn. So, the listener, or rather their brain, is actively predicting when important speech events will happen, using prosody. How prosodic rhythms are exploited to predict speech timing, however, is unclear. No link between prosody and neural predictive processing has yet been empirically made. One hypothesis is that rhythm, such as the alternation of stressed and unstressed syllables, helps listeners time their attention. Similar behavior is best captured by the notion of an internal oscillator which can be set straight by attentional spikes. While neuroscientific evidence for the relation of neural oscillators to speech processing is starting to emerge, no link to the use of prosody nor predictive listening exists, yet. Furthermore, it is still unknown how native language knowledge affects cortical oscillations, and how oscillations are affected by cross-linguistic differences in rhythmic structure. The current project combines the standing knowledge of prosodic typology with the recent advances in neuroscience on cortical oscillations, to investigate the role of internal oscillators on native prosody perception, and active speech prediction.
