Cotton, Sesame, and Copper: Five Thousand Years of Silence Broken — Decoding the Harappan Script as a Bronze Age Trade Certification System

We present Compositional Position Theory (CPT), a framework for partial decipherment of the Harappan script based on the systematic positional distribution of signs across the inscription corpus. The Harappan corpus is heterogeneous, comprising stamp seals and clay sealings from warehouse and trade contexts, personal identity tablets, domestic objects, and civic or ritual inscriptions. CPT's three-position grammar — an authority HEADER sign at text-beginning, commodity or guild signs in MEDIAL position, and a certification TERMINAL sign at text-end — is proposed specifically for the trade-context subset: stamp seals and warehouse sealings, which constitute the dominant inscription type by token frequency. Claims in this paper apply to this subset and should not be read as universal across all inscribed objects. We identify 15 signs with Proto-Dravidian etymologies assessed under a formal three-criterion confidence rubric (ICIT positional confirmation, DEDR etymological regularity, and independent external attestation), covering approximately 52% of corpus sign occurrences by token frequency across all inscription types. The 27 inscription readings presented here are conditional findings: they follow directly from the sign assignments and carry corresponding confidence levels. We document 16 grammar variants whose site-specific distributions are consistent with a multi-stage commodity certification system, presented as a framework for future investigation rather than a concluded finding. We perform the first vector-geometric analysis of the Dholavira Signboard, provisionally reading the world's oldest known civic inscription as 'the seasonal tribute citadel' at 72% confidence pending identification of two unresolved signs. Six converging lines of evidence support the framework, two of which — the ICIT computational validation and the Meluhha cuneiform commodity record — are fully independent of CPT and of each other. Etymological assignments are subject to review by a specialist in comparative Dravidian linguistics; revisions arising from that consultation will be incorporated. These results constitute the strongest systematic evidence to date for a trade-administrative function of Harappan stamp seals and warehouse sealings, decipherable through Proto-Dravidian positional analysis.