Institutional English examines language not as a communication skill, but as a governance infrastructure. In high-consequence environments-regulatory bodies, multinational operations, compliance systems, and executive decision forums-uncontrolled language functions as systemic risk.This work presents a layered framework for treating English as an engineered medium through which authority is exercised, decisions are recorded, and institutional memory is preserved. It addresses linguistic standardisation, register discipline, documentation architecture, post-explanatory records, ambiguity management, and the distribution of power through written artefacts.Rather than offering fluency training or stylistic guidance, the book focuses on structure: templates, metadata schemas, governance mechanisms, and decision-locking practices that allow decisions to remain stable across time, organisational turnover, and jurisdictional boundaries. Case illustrations and operational artifacts are included to support direct institutional deployment.This volume is intended for senior professionals, governance teams, policy owners, and institutional leaders operating in environments where linguistic precision directly affects legal exposure, operational continuity, and reputational stability.