Pronounced "yock", it combines the words YACK and TALK, and refers to the act of just babbling endlessly without much meaningful/legitimate content.
Radio listener, irritably switching off a live interview of a politician bragging about all the supposed "progress" he's made in his still-squalid jurisdiction: Okay --- enough of that BS... got better things to do than listen to HIS yalk for the next two hours!
When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.