Introduction to Verb Scales (Abwab): Trilateral & Quadrilateral

1. From Conjugation to Classification

The next stage of Sarf asks a new question: how is a verb classified before we study its detailed pattern?
Two features are used in this level:
1. How many original root letters does it have?
2. Does it contain only those original letters, or are extra letters added?
These two questions create the basic map used in Munsha'ib.

2. First Division: Three or Four Root Letters

The first classification depends on the number of original root letters.

ExampleOriginal root lettersClass
نَصَرَ3Thulaathi
ضَرَبَ3Thulaathi
بَعْثَرَ4Rubaa'i

Thulaathi therefore means a form with three original root letters; Rubaa'i means one with four.

3. Second Division: Mujarrad or Mazeed Feeh

After root count, ask whether extra letters have been added.

DefinitionType
only the original root lettersMujarrad
original root letters plus one or more extra lettersMazeed Feeh

Example of Mujarrad: نَصَرَ.
A form such as اِجْتِنَاب illustrates the presence of added letters beyond the original root.

4. The Four Basic Verb Classes

Combine the two divisions and four basic classes appear.

Extra lettersRoot lettersClass
No3Thulaathi Mujarrad
Yes3Thulaathi Mazeed Feeh
No4Rubaa'i Mujarrad
Yes4Rubaa'i Mazeed Feeh

This four-box map is the foundation for the detailed Abwab that follow.

5. A Two-Step Classification Method

Use this order:
1. Identify the number of original root letters: 3 or 4.
2. Check whether any extra letters have been added.
If the answer is 3 + no extra letters, the class is Thulaathi Mujarrad.
If the answer is 4 + no extra letters, the class is Rubaa'i Mujarrad.
The same method identifies the two Mazeed Feeh classes when extra letters are present.

6. Classify the Examples

Apply the two-step method to the examples already introduced.

ClassificationReasonExample
Thulaathi Mujarrad3 original letters, no extra lettersنَصَرَ
Thulaathi Mujarrad3 original letters, no extra lettersضَرَبَ
Rubaa'i Mujarrad4 original letters, no extra lettersبَعْثَرَ

The purpose is not to memorize labels separately, but to derive the label from the two questions.

7. A Simple Map of the Level

Remember these points:
1. Thulaathi has 3 original root letters.
2. Rubaa'i has 4 original root letters.
3. Mujarrad contains only original root letters.
4. Mazeed Feeh contains original root letters plus extra letters.
5. Combining these two divisions gives 4 basic verb classes.