Long vowels

Three of the 28 letters in Arabic may function as vowels:
ا - alif
The ا sounds like “a”, like the first “a” in “Pakistan”.
و - waw
The و sounds like “u”, as in “Utah”.
ي - ya
The ي sounds like “ee”, as in “Cheese”.
These three vowels are all long vowels, which have elongated pronunciation.

Short vowels

There are also three short vowels, pronounced similarly to the three long vowels.
Fatha is denoted with a mark above a letter. It is pronounced like ا or like the “a” in “hat”.
كَلب (kilehb) - dog
Damma is denoted with a mark above a letter. It is pronounced like the vowels in “boot”.
فُندُق (funduq) - hotel
Kasra is denoted with a mark below a letter. It is pronounced like the vowels in “feet”.
كِتاب (kitab) - book

The letters often vary in how they are written, depending on their position in a word or sentence.
For example, look at the س
طقس - weather, pronounced “taqs” or “tox”
سيارة - car, pronounced “sayyarra”
س - unconnected letter