Well, he speaks Geordie but he doesn't use slang with me. He started speaking slower but now he says he is speaking at a normal pace and I can understand every single word he says. 

I know that other people use slang and things but when I play a video on YouTube , I can't understand it as well as I do with my friend..it drives me crazy..

It's the same for him...he understand most what O say but not understand others in the same way.

He says that he doesn't soften his accent for me but I think he does without realising.

I do soften my accent for him but he is still a beginner.

Thanks for your reply guys and sorry for my mistakes!!