What is Mandarin Pin Yin?
Pin Yin is a system developed in the 1950's to transcribe Chinese Mandarin sounds using the roman alphabet. It is also frequently used as a way to input chinese text into the computer.
On top of each of the words, you will find a symbol, like this:
This symbol indicates the "tone" of the character. There are 5 main tones in Mandarin.
If you ever see a Pin Yin that you are not sure how to pronounce, you can refer to this interactive Pin Yin chart on Yabla.com. You can mouse-over the Pin Yin and play a sound clip of all the different possible tones for that word!
Please note that there are some "special tone conversion rules" in pin yin. For example, if there are two words that have the 3rd tone in a row, then the first word would automatically change to the 2nd tone. However, according to Pin Yin protocol, both of the words are still written with the 3rd tone. So just watch out for that!
This is further explained on this site here.