The Rule of the Muʿrab: Visible and Estimated Case

1. The Rule of the Muʿrab: Visible Case

فَصْلٌ: وَحُكْمُهُ أَنْ يَخْتَلِفَ آخِرُهُ بِاخْتِلَافِ الْعَوَامِلِ اخْتِلَافًا لَفْظِيًّا، نَحْوُ: «جَاءَنِي زَيْدٌ، وَرَأَيْتُ زَيْدًا، وَمَرَرْتُ بِزَيْدٍ».
Translation: Section: Its rule is that the ending of a declinable noun varies as its governing factors vary—sometimes through a visible change. For example: “Zayd came to me; I saw Zayd; and I passed by Zayd.”

Key observation
The same noun occurs three times. Its ending shows ḍamma, then fatḥa, then kasra. This is the book's example of overt/visible case marking.

2. The Rule of the Muʿrab: Estimated Case

أَوْ تَقْدِيرِيًّا، نَحْوُ: «جَاءَنِي مُوسَىٰ، وَرَأَيْتُ مُوسَىٰ، وَمَرَرْتُ بِمُوسَىٰ».
Translation: Or the variation may be estimated (not pronounced), as in: “Mūsā came to me; I saw Mūsā; and I passed by Mūsā.”

The written and pronounced form «مُوسَىٰ» stays the same, but its syntactic case is first nominative, then accusative, then genitive. Its final alif maqṣūra cannot carry an overt case vowel.

3. Understand the textbook wording

وَحُكْمُهُ — “and its ruling”: “its” refers to the declinable noun from the previous lesson.
أَنْ يَخْتَلِفَ آخِرُهُ — “that its ending should vary.”
بِاخْتِلَافِ الْعَوَامِلِ — “with the variation of the governors.”
اخْتِلَافًا لَفْظِيًّا — “an outward, perceptible change.”
أَوْ تَقْدِيرِيًّا — “or an estimated change.”

Combined meaning: the governing context determines the case of a muʿrab noun, but the ending may or may not show the case vowel overtly.

4. What is an ʿāmil?

An ʿāmil (governor) is an element that causes or determines a grammatical case in a related word. The word governed is called the maʿmūl.

جَاءَنِي زَيْدٌ
Translation: Zayd came to me.
The verb «جَاءَ» governs its subject in the nominative.

رَأَيْتُ زَيْدًا
Translation: I saw Zayd.
The verb «رَأَيْتُ» governs its direct object in the accusative.

مَرَرْتُ بِزَيْدٍ
Translation: I passed by Zayd.
The preposition «بِـ» governs the noun in the genitive.

5. First textbook example: nominative

جَاءَنِي زَيْدٌ
Translation: Zayd came to me.

Parsing
جَاءَ: past-tense verb, built on fatḥ.
نِ: protective nūn before the first-person suffix.
ي: attached first-person pronoun, in the accusative object position.
زَيْدٌ: subject, nominative, with an overt ḍamma.

Why?
Zayd is the one who arrived, so the noun is the subject. The ḍamma on the ending is visible.

6. Second textbook example: accusative

رَأَيْتُ زَيْدًا
Translation: I saw Zayd.

Parsing
رَأَيْتُ: past-tense verb with the attached subject tāʾ; the verb is built on sukūn in this form.
تُ: attached pronoun in the nominative subject position, meaning “I.”
زَيْدًا: direct object, accusative, with an overt fatḥa.

Why?
“I” performed the seeing; Zayd is the person seen. Therefore Zayd is the direct object and takes the accusative.

7. Third textbook example: genitive

مَرَرْتُ بِزَيْدٍ
Translation: I passed by Zayd.

Parsing
مَرَرْتُ: past-tense verb, whose attached تُ is its subject.
بِـ: preposition; in this context, “by/past.”
زَيْدٍ: genitive noun, with an overt kasra.

Important
The noun is genitive because of the preposition «بِـ», not because the past verb alone directly assigns genitive case.

8. One noun, three visible endings

جَاءَنِي زَيْدٌ
Translation: Zayd came to me.
زَيْدٌ ← subject; nominative; ḍamma.

رَأَيْتُ زَيْدًا
Translation: I saw Zayd.
زَيْدًا ← direct object; accusative; fatḥa.

مَرَرْتُ بِزَيْدٍ
Translation: I passed by Zayd.
زَيْدٍ ← prepositional noun; genitive; kasra.

Remember
It is still the same person and noun. The syntactic role and the overt case vowel change. The text calls this اخْتِلَافًا لَفْظِيًّا.

9. Do not confuse the governor and the case sign

The governor (ʿāmil) and the case sign are different things.
The governor causes the grammatical status; the case sign makes that status visible.

جَاءَنِي زَيْدٌ — Zayd came to me.
Governor: verb «جَاءَ». Sign: ḍamma.

رَأَيْتُ زَيْدًا — I saw Zayd.
Governor: verb «رَأَيْتُ». Sign: fatḥa.

مَرَرْتُ بِزَيْدٍ — I passed by Zayd.
Governor: preposition «بِـ». Sign: kasra.

10. Why Mūsā does not show an ending

مُوسَىٰ is a declinable noun, but it ends in an alif maqṣūra. An overt ḍamma, fatḥa, or kasra cannot be pronounced on that final alif.
The grammatical nominative, accusative, and genitive positions still exist. The relevant case ending is therefore said to be estimated rather than visible.

Crucial distinction
The absence of a visible vowel does not mean the noun has no governor. It is governed; the ending simply cannot display its case vowel.

11. Mūsā as the subject

جَاءَنِي مُوسَىٰ
Translation: Mūsā came to me.

جَاءَنِي: past verb with the first-person object suffix, “to me.”
مُوسَىٰ: subject, nominative, with an estimated ḍamma.

Why is the ḍamma not visible?
Because the word ends in alif maqṣūra; a case vowel cannot be expressed on it. Traditional grammar calls this taʿadhdhur (impossibility).

12. Mūsā as the object

رَأَيْتُ مُوسَىٰ
Translation: I saw Mūsā.

رَأَيْتُ: past verb with the attached subject tāʾ.
مُوسَىٰ: direct object, accusative, with an estimated fatḥa.

Compare
رَأَيْتُ زَيْدًا — I saw Zayd; overt fatḥa.
رَأَيْتُ مُوسَىٰ — I saw Mūsā; estimated fatḥa.

Both nouns are direct objects. Their syntactic role agrees; only how the ending is expressed differs.

13. Mūsā after a preposition

مَرَرْتُ بِمُوسَىٰ
Translation: I passed by Mūsā.

بِـ: preposition.
مُوسَىٰ: genitive noun, with an estimated kasra.

Compare
مَرَرْتُ بِزَيْدٍ — I passed by Zayd; overt kasra.
مَرَرْتُ بِمُوسَىٰ — I passed by Mūsā; estimated kasra.

The preposition makes both nouns genitive, whether or not the vowel is visible.

14. Visible does not mean written letters change

Overt case change does not require changing the root letters of a name.

زَيْدٌ، زَيْدًا، زَيْدٍ
Translation: the same name with three different case endings.

The consonants of Zayd are unchanged; the ḍamma, fatḥa, and kasra differ. Unvowelled writing may conceal these differences, but they are still real case endings.

Do not conclude that a noun is indeclinable or has estimated case merely because an unvowelled text looks unchanged.

15. Estimated muʿrab is not mabnī

Last lesson used «هَؤُلَاءِ» as an indeclinable noun. Here «مُوسَىٰ» introduces another situation.

مُوسَىٰ: declinable; its nominative, accusative, and genitive case signs are estimated.
هَؤُلَاءِ: an indeclinable demonstrative; it can fill different syntactic positions without changing its fixed form.

Core distinction
With estimated case, a muʿrab noun has case vowels that cannot surface. With mabnī, the fixed ending does not change through the governors; the noun can instead be described as occupying a case position.

16. Practice: three extra examples

These are supplementary examples, not quotations from the textbook. Identify each governor and case before reading its analysis.

حَضَرَ خَالِدٌ
Translation: Khālid arrived.
خَالِدٌ: nominative subject with overt ḍamma.

أَكْرَمْتُ خَالِدًا
Translation: I honored Khālid.
خَالِدًا: accusative object with overt fatḥa.

سَلَّمْتُ عَلَى خَالِدٍ
Translation: I greeted Khālid.
خَالِدٍ: genitive after «عَلَى», with overt kasra.

17. Lesson conclusion and self-check

1. The ending of a declinable noun is governed by changing grammatical factors.
2. زَيْدٌ، زَيْدًا، زَيْدٍ demonstrate visible case endings.
3. In مُوسَىٰ, ḍamma, fatḥa, and kasra are estimated because the final alif maqṣūra cannot show them.
4. The governor is not the same thing as the case sign.
5. Estimated case is different from indeclinability.

Self-check
What is the case of «مُوسَىٰ» in «رَأَيْتُ مُوسَىٰ»?
Answer: accusative direct object, with an estimated fatḥa.

Next lesson begins the book's next section, «أَصْنَافُ إِعْرَابِ الِاسْمِ».