Complete internationalization implementation for web applications. Provides systematic AI-driven workflow to achieve 100% i18n coverage with zero hardcoded strings in SOURCE CODE. Use for adding i18n to new projects, migrating hardcoded strings to i18n, adding new language support, or auditing i18n coverage. CRITICAL: This skill focuses ONLY on source code internationalization (components, views, UI), NOT documentation files (README.md, docs/). When checking for existing i18n, prioritize src/ directory detection and ignore docs/, README*, and markdown files. Includes extraction patterns, component migration strategies, namespace organization, and validation checklists. Works with React, Vue, Angular, and similar frameworks.