The most difficult about English? I think grammar, of course!
The grammar and the pronunciation...it's hard.
To learn grammar.
In adult education one of the foundational elements is to be able to engage with adults on the level of motivation where they're at.
Reminding them with the grammar that it actually is teaching you how to speak the language and how do you connect the sentences and how do you put the words together.
When I teach grammar, I don't have them simply memorize rules. I want them to see the system, I want them to see how these parts of grammar fit together, and I think the Grammar in Context series helps me to do that.