Full Site Editing themes should support internationalization (i18n) and localization (l10n).

The process to extract and localize is summarized by this diagram.

Requirements

• To be able to use the Fizzie theme in the user's selected locale.
• To automatically extract and localize templates and template parts.
• Test with two additional languages:

1. UK English - locale en_GB
2. bbboing's language bb_BB

Proposed solution

• Create localized versions of the templates and template parts delivered by Fizzie.
• Use the automated tools developed in FSE - Can we internationalize .html files without requiring any special markup? oik-i18n#7
• Use a batch routine t10n.bat to automate the translation into UK English and bbboing.
• Update Gutenberg and/or Fizzie to support loading of translated templates and template parts
• Test for UK English ( en_GB ) and bbboing ( bb_BB ).

Requirements on Gutenberg

• Gutenberg's template and template loading logic needs to be updated to take into account the user's locale.
• The translated files will be stored in subfolders of the languages folder, with one directory per supported locale.
• If the directory isn't present the US English files are used.

Assumptions, scope, exclusions and caveats

• Templates and template parts are inherently static; they don't implement conditional / looping logic.
• Internationalization (i18n) of the templates and template parts is only necessary for certain strings which should not be translated.
• As such, localized versions can be created at build time, or whenever the translations are updated.
• Blocks used in templates and template parts may implement conditional / looping logic.
• These blocks are usually server side rendered using PHP.
• A theme's PHP code will be localized using makepot.
• Any JavaScript blocks delivered by the theme will be localized using makejson.
• The solution should support all locales and character sets currently supported by WordPress.
• The solution should support themes which are not delivered from wordpress.org

Limitations of the prototyped solution

• t10n.bat is currently dependent upon oik-batch's oik
• The current routines are prototyped batch routines which echo debug information.
• Not all scenarios are yet catered for by the routines invoked by t10n.
• The current solution doesn't merge .pot files into one file prior to translation.
• But text strings used in PHP and template files and parts are not expected to be the same.
• So there shouldn't be too many duplicate strings to translate.