when i tell you something , and you want to tell me that you understood it , you can say : # " ana fahim or only fahim " " فاهم - انا فاهم " in English understanding . ( informal ) Also you can say # " ana afham ma takol" aw " maza kolt " in English " I am understanding what do you say or I am understanding what did you say " . ( formal - standard Arabic ) - Don't say " an afhm or afham " and stopping here because it may seem that somebody asked you in general about your understanding , your mind . Do you understand ( do you have mind ) ? - yes , i do ( yes i understand , yes i have mind , afham ! ) * wish i could help !

انا افهم is standard Arabic. انا فاهم is Egyptian dialect.

First of all, both of them can be used in standard Arabic. But in Egypt we use أنا فاهم. If you're talking in Egyptian dialect, then it's better to say أنا فاهم. Hope this helps.

انا افهم