Harakat are small marks placed above or below letters that create vowel sounds — they are essential for correct pronunciation.

Sukoon is a mark that removes the vowel sound so the letter is pronounced as a pure consonant with a complete stop of the vowel.

Shaddah is a mark that doubles a letter so it is pronounced as two letters: the first with sukoon and the second with a vowel.

Tanween is a double vowel marking on the final letter of a word that produces a light 'n' sound and indicates indefiniteness — there are three types based on which vowel is doubled.