Sacrcasm

I've been thinking about sarcasm lately. It's interesting how, by exaggerating just one or two letters, the meaning of a sentence is reversed. 

In the following examples, the sarcasm (and therefore the reversal of the sentence's original meaning) is underlined. Try saying them normally, and then again while exaggerating the underlined letters.

  i.e.

  It almost seems like sarcasm lies in the vowels. Are there any other ways to make a sentence sound sarcastic?

how do i exaggerate the u in sure

For Americans, this is definitely true but Europeans and Australians+Newzealanders do sarcasm much drier and with more subtlety.

It is definitely easier to catch American and Canadian sarcasm than British etc.

My sarcasm essentially devolved into this. Literally pretending I don't understand there is any joke so I could either look like an idiot or a genius.

One example:

Person(sarcastically): "The earth is flat, and everyone who says that the earth is round is a NASA government slave!"

Me: "Hello, I am a NASA government slave, and I can confirm here that the earth is completely flat, no need to thank me."