double t

One of my favorite things is to hear people speaking in a British accent. I've been spending the last few weeks with a group of people from Oxford, and loving it. Another thing I've learned is I love to hear the British people mimic an American accent - it sounds so harsh! A friend of mine from home is from South Africa and that's a similar accent. He told a story of going into a hardware store to buy a "batry" and the clerk had no idea what he was saying. "batry" I love hearing that word, it sounds so nice. But in order to finally get his point across he had to mimic the american way to say battery, and he did so quite nicely, and it came out "baadderry". Which is quite accurate. I love how the British are saying "botil" - like a "botil of beer". It's the same thing. But we had someone not understand what they said. So the word was americanized and it came out "bawddle". Why is it we seem to make the double t sound so ridiculous.