If you don’t currently have a solid i18n/l10n foundation, I’d recommend implementing it gradually and in an organized way. The ideal approach is to centralize all visible text in files or a translation management system, using common keys for each message. This helps avoid any hardcoded sections in English. It’s also a good idea to define a fallback language, meaning a backup language that is displayed if any translation is missing, so the interface never appears incomplete. With a module-by-module review and proper tracking of missing strings, you can fix this without making implementation too complicated and leave the app ready to grow into more languages.