Explanation of the words of Ibn Malik (may Allah have mercy on him): "The first is that its inflection is estimated in its entirety *** and it is the one that has been shortened."

The Shaykh : His statement: "The first is that its inflection is estimated in its entirety"
What is the first? The defective word with alif. "The first is that its inflection is estimated in its entirety and it is the one that has been shortened" This means it is called the first shortened word, and the defective word with alif is called the shortened word. You estimate all the vowel movements in it, and no vowel movement appears in it. So you say: "Musa came," "I saw Musa," and "I passed by Musa." The inflection does not change. We say: Musa in the first example: Musa is the subject, raised, and the sign of its raising is a dammah estimated on the alif, prevented from appearing by impossibility. Okay, this is the first. The defective word with alif. What is the defective word with alif?
The student: The defective word with alif.

The Shaykh : You estimate in it.
The student: All the vowel movements.

The Shaykh : All the vowel movements: the fathah, the dammah, and the kasrah. It is restricted to one state and is called the shortened word.