The IPA

Have you ever looked up a word in the dictionary, and next to the word itself there was a bunch of regular letters mixed with weird ones (such as an upside down e or a lambda)? That system of graphemes is what linguists call the IPA, or the International Phonetic Alphabet. The IPA contains hundreds of symbols, thousands if you count possible diacritic modifications.

Why do we use a system with so many symbols if we can express all the sounds in English with the letters we already use? There are several reasons:

• Our alphabet does not have a 1:1 sound to symbol ratio
• Our alphabet cannot not adequately represent all possible human sounds (like clicks in Xhosa etc)
• Using the Latin script puts users of other writing systems at a steep disadvantage
• When we use IPA, we have an easier time transcribing previously unwritten languages
• When investigating a language using the IPA, we aren't required to learn the language's writing system

Those are just a few perks the IPA affords us. In any linguistics textbook you browse through, you are bound to see the IPA scattered throughout; it is an integral means for us to express our findings effectively. 

Here, you can find a basic chart of the IPA: http://upload.wikimedia.org/wikipedia/commons/f/f5/IPA_chart_2005_png.svg

Additionally, here is the website of the organization that standardizes the IPA:

http://www.langsci.ucl.ac.uk/ipa/