Why are there so many flipping vowels in Greek?

If you live in Cyprus and are taking the first step in learning you will find Greek is useful in the written word, but not so much in a shop or on the street.

English being a second language in Cyprus, you still have a backup until you get the hang of it.

Once in a classroom or in front of a computer for an online lesson, a foreigner learning Greek may be baffled by the number of vowels – there are two ‘e’s, two ‘o’s and a staggering five ‘i’s.

Why are there so many flipping vowels?