A course (legacy: Language). Superset read model: the public catalog embeds it, admin course screens read the full shape.

A marketing landing page for a course (legacy: LanguageLandingPage).

The modules of the course's current version in the request locale, in course order — the learning program's accordion. Each names its lessons by slug, joined to lessons for names, so the flat list stays the one source of lesson rows the page and the player share.

The landing page's questions and answers, oldest first; empty without a landing page.

A learner's enrollment in a course (table language_members).

A learner's position in one Course, computed against its current Version.

Availability travels with it even though it is a pure function of position: a client deriving it would be a second implementation of the gate, free to drift from the server that enforces it.