This is a guide to add a new language to a Next.js project using next intl for internationalization, For i18n, the application uses next intl. All translations are in the directory ./messages . The UI component is src/components/language toggle.tsx . Routing and middleware configuration are handled in: src/i18n/routing.ts src/middleware.ts When adding a new language: Translate all the content of en.json to the new language. The goal is to have all the JSON entries in the new language for a complete translation. Add the path in routing.ts and middleware.ts . Add the language to language toggle.tsx .

next-intl-add-language