Note: This flowchart is not fully up-to-date. Please read Plugin Handbook Internationalization documentation for the latest information.

You can now use wp-info.org’s handy tool “Is your plugin i18n ready?” and its Chrome Extension: wp-info.org i18n plugin check.

I made a flowchart for troubleshooting WordPress Plugin translation, in preparation for this weekend. Meetup organizers from 13 cities in Japan are holding Plugin/Theme/Codex translation sprints on May 17th!

An SVG file and Japanese version of the chart (PNG) are also available.