Classical Greek makes use of 7 vowels to represent 10 distinct sounds. For a review of the characters and transliterations, check out the Greek alphabet here. These vowels can be divided into the classifications “long” and “short”:
Note: The line drawn above alpha, iota and upsilon is not found in actual Greek text. Rather, it is a means of indicating that a particular character is pronounced either long or short, found in many Greek study materials.
In addition, vowels can be combined to make a number of diphthongs, groupings of vowels pronounced as a single sound:
|αι||ai||the English pronoun “I”|
|ευ||eu||glide from ε to υ|
|ηυ||ēu||glide from η to υ|
With diphthongs found at the beginning of words, the breathing mark is placed above the second letter in the set. This is a modification of my comment to place it over the first character, as stated in this blog entry.