Explaining Dhamma
Ajaan Paññāvaḍḍho
You asked why it was that you cannot explain Dhamma to other people.
That ability is probably a matter of innate tendencies (most likely based on kamma), and I doubt whether you can do much about it. We read that Acharn Mun was superb at giving talks and explanations of Dhamma, but Acharn Sao (his teacher) would speak only a couple of sentences and go silent; and this despite the fact that he was also an Arahant.
It is just possible that, as your citta develops more in Dhamma, you will be able to teach in a style of your own. Time alone will tell.
This reflection by Ajaan Paññāvaḍḍho is from the book, Dear Jane, (pdf) pp. 419-420.