Lesson perspectives
Student perspective
You should start by reading What is a lesson? which is the view that students have of lessons.
Editor perspective
You should next read the Editor help page on lessons, which gives the slightly more technical view of lessons, describing how editors need to assign each word (and to a lesser degree, each phrase or dialogue) to the correct lesson.
Programmer perspective
A lesson, from a programming point of view, is simply a collection of word content type instances (usually only words or phrases), which are bundled together as a single group, and then used both to display words/phrases together, and also to teach students the words/phrases within that group.
Lesson = Taxonomy term
The grouping together is by them having the same taxonomy term assigned to them.
For example, if the words "dog", "cat" and "sheep" all get the "Animals" term from the "Themed" vocabulary selected, then these three words will form part of a group called a Lesson.
Take a look at the Animals lesson which you will see contains all the words (phrases/dialogues) which have the taxonomy term "Animals". The "Animals" term is part of the taxonomy vocabulary called "Themed".
Since taxonomies are key to understanding the lessons, it would be worth taking a look at the taxonomy vocabulary and term names at http://lingopolo.com/french/admin/structure/taxonomy, e.g.:
- "Themed" (see http://lingopolo.com/french/courses/themed), where "Themed" is the vocabulary and things like "Animals" and "Body parts" are the taxonomy terms
- "Parts of Speech" (see http://lingopolo.com/french/courses/parts_of_speech), where "Parts of Speech" is the vocabulary and things like "Adjectives" and "Nouns" are the taxonomy terms
Manual vs. Automatic Lessons
About half of the lessons are created manually, by for example an editor putting the word "dog" in the "Animals" lesson (or, from a technical perspective, assigning the taxonomy term "Animals" to the "dog" node).
About half of the lessons are created automatically. These are special lessons which editors do not create, but which are created automatically:
- "... Examples" lessons (e.g. Level Examples, Syllabus Examples, Themed Examples)
- Breakdown (one per phrase)
- Practice (one per phrase)
Other than the fact that they are created differently, they still function in exactly the same way:
- words or phrases are assigned by taxonomy terms to belong to the set of words/phrases in that lesson
- students will see a list of words/phrases in that particular lesson
- students will be trained on the list of words/phrases in that particular lesson