Paolo,
I moved up to Scotland from England many years ago.
It took me 2 years to understand 80% of what they said, and another 3 years to be fully able to converse freely.
Basically it is English, but in a very different accent, and with many 'scottish' words derived from Gaelic language too.
Even now I come across a new word from time to time.
So, an Italian listening to drunken Scotsmen has No Chance
Dave