There are a few famous movie scenes where somebody deliberately uses perfectly reasonable English sentences but with such a thick accent that most English users cannot understand it, but once you know what they said you can play that sound back and yeah, that's what they said, you just couldn't understand the accent e.g..

https://www.youtube.com/watch?v=Hs-rgvkRfwc

Indeed the joke is that people keep repeating what the hard-to-understand bloke said even when it's perfectly obvious what he said, because if you can understand it then you can't tell whether it was hard to understand.

That's not even Scottish, the bloke in that scene is from Somerset, which is the far side of the country but exactly like Scotland most people in Somerset don't talk like that most of the time, but some of them do, some of the time and to them it's normal, that's just how you say words.