Halo 4 Specializations?

When you reach SR-50 and unlock the specializations… When you start to use one, does it replace something you already have on (like you no longer have a secondary weapon if use a specialization), or is it just something extra that gets added on?

Specializations aren’t ‘things.’ They’re ranking pathways you take after you’ve made it to the highest normal rank, and allow you to unlock new armor and armor mods.

So the abilities and perks that come with a specialization are just added onto your spartan while you’re using that specialization?