Arabic Grammar consists almost entirely of putting harakaat on letters.
Arabic writing is typically written without the harakaat. How is it possible to read? One must learn slowly, piece by piece, and read with understanding. Arabic is not like English–you have to actively read and consciously think while you read about what it means. (At least, when you start out.)
Why are harakaat important? Harakaat determine the meaning of words and sentences entirely. A different choice of harakaat can sometimes invert the meaning of a sentence entirely!
For example, this word: ضرب (daad-ra-ba) can mean hit (ضَرَبَ: daraba), hitting (ضَرْبٌ: darboon), was hit (ضُرِبَ: duriba), and more! Another word is من (meem-noon) which can mean from (مِن: min) or who (مَن: man), and so on.
InshaAllah ta’ala now that you know, start paying attention to the vowels as you read Qur’an. It makes all the difference.
May Allah (سبحانه وتعالى) grant us all knowledge of Arabic, the language of the Glorious Qur’an, ameen!