Callouts

Everytime I play firefight on Downfall people keep calling out twins, hotel, tower, ect... I had no fucking idea what any of these callouts meant until I got my shit rocked from the people at said callouts. We all have watches and tablets that give you literal direction and numbers. Why don't people call the number instead of hoping everyone knows what they mean when they callout some random shit? Maybe I j need to learn and play more but j a thought to keep it standard and make it easier for everyone.