[Caluabdum]

Among the hardest pronunciation of arabic letters are to differentiate:

ص and س
ذ and ظ

and letters that people take for granted:

ح and ه

and when to have lighten/harden ل in الله

and

I got this from another of my teachers that Maulana Mohammad has had completed quran in one sitting.

I'm wondering how long would that take. Can you ask that too.