Why do variables need Types?

Before I joined Treehouse, I had started programming a bit on C#. Now I know that you guys don't have any c# videos but I was wondering because you guys seem like people that know a lot about programming, you could help me out.

So my question is why do variables need Types? I mean in c# if I was create a new instance of something(lets say a button), I would write: Button myBtn = new Button(); So I get the whole myBtn = new Button(); part but why do you need the first "Button". I also noticed that in your iOs tutorials(Your a great teacher Amit) you also do something similar. When lets say you want to create an array you say: NSArray *myArray = [[NSArray alloc] initWithObjects:....] Like I said before I understand why you need the myArray = [[NSArray alloc] initWithObjects:...] but why do you need to declare the type? I mean cant the system recognize what you put in that variable? Im really confused.... Any help of feed back would be great! Thanks a ton!