Can someone explain to me what these Speciali

zations are? What happens when I reach level 50? And what are the benefits of choosing one of these specializations?

When you pick one you get new Armor, new emblems, a new weapon skill and a new perk. Pioneer for example. When you get threw the ten levels of Pioneer, you unlock a perk that you use in a load out that will grat you more xp in a match. That can help you rank up a little faster. Engineer as another example is a perk where you will be told what Ordnance is about to spwan on the map, giving you more time to get there before it spawns. You have to advance threw the ten levels of each one before you unlock the perk that goes with it but once you do you cna change your loadouts and use any you have unlocked.