I am a StarCraft fan and I have no idea what a courtyard or a frontyard is supposed to be! However I do know that the names of buildings, units, technologies, and strategies are usually heavily abbreviated in English. Perhaps the same is true in Korean? A 12 barracks build would usually just be called "12 rax", a two hatchery mutalisk build would be called "2 hatch muta", and a three hatchery hydralisk timing attack / all-in would be called "3 hatch hydra bust".
A lot of Korean slang is a little different. Source: not Korean but have been in the English community a long time and picked some stuff up.
"1rax double" is equivalent to "1rax expand" or "1rax CC". They use multi or double to mean expand in the early game. Instead of "cheese" or "all-in" they use "pil-sal-gi" which means ace/joker card or "han-bang" which means an army or attack on few resources.
I am not sure what short-hand they use for barracks, gateway, etc.
The numbers indicate the supply you should be at when you build the structure.
so a 12 hatch 12 pool 12 gas means you get to 12 workers and then build those 3 buildings in that order as soon as you have the resources for those.
For zerg the workers actually become the building, so I assume you hit 12, build the hatchery, build another worker, build the spawning pool, build another worker, and then build your gas refinery.
As you get later into the game people who play more seriously also use the in-game clock, or timing a building placement relative to how complete a different building is to determine building timing. This helps with subtleties like whether you lost your scouting worker or not (-1 supply), if the early game got really weird because you had to build more units to hold some aggression, etc.