There are no significant differences between English 8 and the Advanced Grammar course. They both include
many of the same grammar concepts and utilize sentence diagramming.
Advanced grammar does, however, cover more advanced grammar concepts like cognate verbs and adverbial objectives. Usually, students who take
Advanced Grammar are students who have an affinity for grammar and
sentence diagramming, want to include an additional English elective on
their transcript, and/or want to polish their already-solid
understanding of English grammar.
The Fundamentals of Grammar Course is more of a remedial course for incoming HS students that are new to Seton and may have not received a proper foundation in grammar/mechanics. Since our full-credit HS English courses do not cover grammar (assuming the student already knows proper grammar), newer students are automatically enrolled in Fundamentals since they will need to write many essays using proper grammar. As you can see on https://www.setonhome.org/high-school/english/fundamentals-of-grammar/, the course uses the Easy Grammar Plus grammar texts but is directed by the lesson plans found in the Fundamentals of Grammar Course Manual.
If a student is weak in grammar or struggles with sentence
diagramming, I would suggest the student take Fundamentals of Grammar.
As the title of the course suggests, it does cover all the foundational
skills needed to write clearly, grammatically-correct sentences, a
needed baseline to succeed in the writing demands of the HS courses.
You can also look at a sample of the lesson plan by clicking "View Sample Lesson Plans" on our website at:
https://www.setonhome.org/high-school/english/fundamentals-of-grammar/
https://www.setonhome.org/high-school/english/advanced-grammar/