nextjs-build-website-i18n

Next.js bilingual i18n is implemented using next-intl v3 to configure server-side message loading, middleware locale detection, and localized URL pathname mapping. This establishes the foundation for Vietnamese-default and English language support across the App Router.

Internal links lose their locale prefix when standard anchor tags are used instead of typed routing helpers. Enforcing typed internal links preserves the locale prefix, ensuring the language switcher correctly maintains the VI or EN routing context during navigation.

Localized URL pathnames are mapped per locale using next-intl routing configuration, translating route slugs like /san-pham to /products. This provides better SEO and user experience by serving localized paths based on the detected language.

Missing UI strings occur when VI/EN message JSON keys lack symmetry, causing builds to silently fall back. Ensuring symmetric message keys across both language files prevents missing text and maintains translation quality during the internationalization process.

Yes, next-intl v3 routing configuration is required to add English support to an existing Next.js site. It manages the server-side request locale handling, middleware matcher coverage, and localized pathname mapping necessary for bilingual VI/EN functionality.

Adding a second language risks broken links and missing UI text if you miss routing, middleware, and message parity. Known constraints include ensuring middleware matcher coverage and maintaining symmetric VI/EN message keys to prevent silent build fallbacks.