Lines to Sing: The Complete Acoustic Decipherment of Rongorongo

This paper presents an acoustic decipherment framework for Rongorongo, the undeciphered script of Easter Island (Rapa Nui, c. 13th–19th century CE). Building on the resonance notation hypothesis previously applied to the Indus Valley Script (Rios, 2026a; DOI: 10.5281/zenodo.19106373) and the Vinča Script (Rios, 2026b; DOI: 10.5281/zenodo.19139793), we propose that Rongorongo is not a linguistic writing system but a functional acoustic notation system — specifically, a chanting performance guide encoding wave physics, frequency, amplitude, and harmonic instruction. Three convergent pillars of evidence are presented: (1) systematic sign morphology analysis revealing a complete biological frequency scale consistent with Pacific acoustic traditions; (2) Helmholtz resonance calculations demonstrating that every Rongorongo-inscribed non-tablet object calculates to a musically significant frequency, with the Tangata Manu statuette achieving 99.3% accuracy for C5; and (3) cross-civilizational corroboration with the Marshall Islands mattang stick chart system. The original Rapa Nui name for the tablets — kohau motu mo rongorongo, meaning 'lines to sing' — confirms the acoustic function. Five falsifiable predictions are provided. Copyright © 2026 Abelardo Rios Jr.