Phase-locking of oscillatory acoustic signals reflects syllable progression and variation

While a common linguistic view of the cognitive representation of speech is that it is composed of sequenced syllable units, how exactly syllables as abstract cognitive compositional structure relate to quantifiable patterns in the observable signals of articulation and acoustics remains opaque. Previous work has suggested that oscillatory acoustic properties can serve to link linguistic representations and physical events (Tilsen & Arvaniti 2013). We further probe this relationship by testing the temporal coordination between oscillatory signal measures—changes in spectral energy and in amplitude—and syllable boundary locations through the use of phase-locking analyses (Lancia et al. 2023). Results in both English and Tashlhiyt for vocalic and consonantal syllabic nuclei show significant phase-locking values (PLVs) and demonstrate that these signal measures track syllable progression across typologically different languages. Furthermore, the cross-language preferences in syllable nucleus types are reflected in their respective PLVs. Specifically, vocalic nuclei exhibit the highest PLVs, followed by wide aperture consonantal nuclei (sonorants), and lastly by consonantal nuclei with narrow-to-closed constrictions (obstruents). Overall, the findings demonstrate a tight coordination between abstract syllable units and quantifiable signal properties and additionally provide novel dynamical grounding for cross-linguistic nucleus preferences.