In Arabic, a vowel is called “Harakah.”
A letter having a vowel sign is called “Mutarrikh”.
If a letter is without a vowel sign, it is called “Saakin” (resting)
Where a sign appears over a letter which point out a “Saakin” letter, it is called a “Sukoon”(Jazm)
And where there is a leter with any short vowel sign and the next letter has a “sukoon” sign, then both letters will jointly produse a single (syllable) uninterrupted sound