Vowels are not written as letters in Arabic. It's possible to know which vowel to pronounce if you had the حركات (form character) which denotes the way the letter must be pronounced. In Arabic, basically, there are 3 ways you can pronounce each of the 28 letters. e.g., the letter أ , is pronounced as A. أَ = Aa إِ = E أُ = Ao If the word had these forming characters (which signify the vowels), it is possible to know how the word is pronounced. Arabs, however, figure it out intuitively.

Unfortunately, there is no way. However, the last vowel of every word can be predicted according to grammar, but middle vowels depend on your knowledge of the word. After you know more and more vocabulary, you will soon be able to "predict" the vowels in the middle and beginning, until it soon becomes second nature.

Arabic is based on patterns, so yes depending on the context and on the grammatical function, people can guess the words they don't know. But this analogical ability comes with a lot of practice (reading and listening).

no , you have to know the pronounce of the Alphabet to read any word