Formal Arabic uses six
vowels, three short vowels and three long vowels. However, the modern
spoken dialects of Arabic use more than those six vowels. I am not sure
about the total number of vowels used in all the dialects, but I am going
to put here the major ones (and probably these are the ones that matter).
Since that modern dialects
are not written but only spoken, there are not any rules or standards for
writing them down. There are also not any Arabic letters or symbols that
represent the modern vowels that are not present in the classical
language. Therefore, it is totally arbitrary and up to each person to
decide for himself how to write them.
I am not going to invent
any new Arabic symbols, I will just use the way of writing that is closer
to what happens in real life.
I know that my Romanization of vowels in
general is not very methodological, but my purpose was to make it as
closer as possible to written English.