Hebrew vowels

Judaism 101: "www.jewfaq.org" - I can't make this stuff up.

"Like most early Semitic alphabetic writing systems, the alefbet has no vowels. People who are fluent in the language do not need vowels to read Hebrew, and most things written in Hebrew in Israel are written without vowels.
However, as Hebrew literacy declined, particularly after the Romans expelled the Jews from Israel, the rabbis recognized the need for aids to pronunciation, so they developed a system of dots and dashes called nikkud (points). These dots and dashes are written above, below or inside the letter, in ways that do not alter the spacing of the line. Text containing these markings is referred to as "pointed" text.
Most nikkud are used to indicate vowels. The table at right illustrates the vowel points, along with their pronunciations. Pronunciations are approximate; I have heard quite a bit of variation in vowel pronunciation.
Vowel points are shown in blue. The letter Alef, shown in red, is used to illustrate the position of the points relative to the consonants. The letters shown in purple are technically consonants and would appear in unpointed texts, but they function as vowels in this context."