Syntax: Discussion Points

• How do we determine if a sentence is "grammatically correct"?
• Can you make generalizations about sentence structure in English or another language? E.g., how do we form questions in English for sentences with a "be" verb like "He is working in the garden"? Can you define a syntactic rule that would apply to all questions like these?
• Someone must have thought, at some point, that tree diagrams are a good idea. Can you imagine why? Can you diagram some simple sentences?