Learn to internationalize! Connect quickly with learning resources that guide you in applying internationalization to your content development, implementation, etc. Including: Techniques for content developers; a Developer checklist and Language enablement.

If you internationalize, you design or develop your content, application, specification, in a way that ensures it will work well for, or can be easily adapted for, users from any culture, region, or language.
https://www.w3.org/International/i18n-drafts/nav/learn