No matter where you are, what you do in life, clear communication is important.
In any infantry unit, grammer aids in little things like clear, concise orders - giving & recieving them for example.
Or in understanding the wee little lessons the RIP cadre might care to impart to you, if it doesn't ruffle your feathers, that is.
If you ever get to RIP, or whatever PJ selection is called, you'll need to check your ego at the door. No one cares what you were, only what you have on the Day. It works the same way when you face an armed enemy in the three dimensions, as a significant number here have, the ones who were "rudest" to you in particular.
We're not friendly to outsiders for a reason. Live with it or leave.
Most everything you'd want to learn, outside of whether or not you have the guts for Ranger selection, is on one or another forum here somewhere.
Should you manage to take the leap and make it to RIP (or PJ or Underwater Messkit Repair, wherever) graduation, make sure you show back up & say "Gotcha ya F****rs!".
We'll welcome you then.
But then, of course, you'll have to deal with being a cherry private in Regiment.
Have a good time in Myspace.