Negating the Imperfect with Lan and Lam: Subjunctive, Jussive and Full Paradigms

1. Two further ways of negating the imperfect

The imperfect can express present or future meaning. The preceding lesson used لَا يَفْعَلُ for ordinary negation. This section introduces two particles that change not only the meaning but also the ending of the imperfect.
لَنْ يَفْعَلَ — he will not do it (with emphatic future negation).
لَمْ يَفْعَلْ — he did not do it (past negation).
The verb remains imperfect in form. But lan puts it in the subjunctive (naṣb), whereas lam puts it in the jussive (jazm). These govern the ending or cause an inflectional nūn to drop.

2. Future and past negation

لَنْ denies an action in the future. The textbook calls this nafy-i taʾkīd, an emphatic expression of future negation.
لَنْ يَكْتُبَ — he will not write.
لَنْ يَسْمَعَ — he will not hear.
لَمْ places the imperfect in a past-negative construction, termed nafy-i jaḥd.
لَمْ يَكْتُبْ — he did not write.
Do not infer from lan alone that the event is impossible for all eternity. Its primary function in this lesson is future negation, with emphasis determined by context.

3. Lan changes final ḍamma to fatḥa

Lan governs the subjunctive (naṣb). In the five conjugation positions whose ordinary indicative imperfect ends in a ḍamma, that ḍamma becomes a fatḥa.

Word / formMeaning / explanation
يَفْعَلُ ← لَنْ يَفْعَلَhe will not do.
تَفْعَلُ ← لَنْ تَفْعَلَyou (masc.) will not do, or she will not do.
أَفْعَلُ ← لَنْ أَفْعَلَI will not do.
نَفْعَلُ ← لَنْ نَفْعَلَwe will not do.

Correct negation requires both the particle and the appropriate change to the verb ending.

4. Deletion of the inflectional nūn after lan

Several imperfect forms end in -āni, -ūna or -īna. The final nūn in these endings is the inflectional nūn. It remains in the indicative but is deleted in both the subjunctive and jussive.

Word / formMeaning / explanation
يَفْعَلَانِ ← لَنْ يَفْعَلَاthe two males will not do.
يَفْعَلُونَ ← لَنْ يَفْعَلُواthe males will not do.
تَفْعَلِينَ ← لَنْ تَفْعَلِيyou (fem. singular) will not do.

The retained alif, wāw or yāʾ still identifies the dual, masculine plural or second-person feminine singular position.

5. Seven paradigm positions governed by nūn-deletion

The textbook's nūn-deletion rule applies to seven positions in the fourteen-slot paradigm. Seven positions do not necessarily mean seven different written shapes; some positions coincide.
Third person: يَفْعَلَا، يَفْعَلُوا، تَفْعَلَا.
Second person: تَفْعَلَا، تَفْعَلُوا، تَفْعَلِي، تَفْعَلَا.
For example, لَنْ تَفْعَلَا appears for a pair of males and a pair of females being addressed, and also for two females spoken about. Pronouns and sentence context determine the intended person.

6. Why the feminine-plural nūn remains

The final nūn in يَفْعَلْنَ and تَفْعَلْنَ is the nūn of the feminine plural (nūn al-niswah), not an inflectional nūn. As a marker of feminine-plural person, it is not deleted by lan.
يَفْعَلْنَ ← لَنْ يَفْعَلْنَ — the women will not do.
تَفْعَلْنَ ← لَنْ تَفْعَلْنَ — you women will not do.
Contrast يَفْعَلُونَ ← لَنْ يَفْعَلُوا, where the inflectional nūn does drop. Not every final nūn has the same function.

7. Lan with passive imperfect forms

In the passive imperfect, the subject is the person or thing acted upon rather than the agent performing the action. Lan governs the same subjunctive endings in passive forms as in active forms.

Word / formMeaning / explanation
يُفْعَلُ ← لَنْ يُفْعَلَit will not be done to him/it.
يُفْعَلَانِ ← لَنْ يُفْعَلَاit will not be done to the two.
يُفْعَلُونَ ← لَنْ يُفْعَلُواit will not be done to those males.

The passive template retains ḍamma on the imperfect prefix and fatḥa before the final radical; lan changes the case/mood ending.

8. Lan: masculine third-person paradigm

Lan: active | passive

FormActivePassive
Third-person masc. singularلَنْ يَفْعَلَلَنْ يُفْعَلَ
Third-person masc. dualلَنْ يَفْعَلَالَنْ يُفْعَلَا
Third-person masc. pluralلَنْ يَفْعَلُوالَنْ يُفْعَلُوا

The singular changes final ḍamma to fatḥa; the dual and plural lose their inflectional nūn. Active meaning denies what the subjects will do, while passive meaning denies what will be done to them.
لَنْ يَفْعَلُوا — they (masc.) will not do.
لَنْ يُفْعَلُوا — it will not be done to them.

9. Lan: feminine third-person paradigm

Lan: active | passive

FormActivePassive
Third-person fem. singularلَنْ تَفْعَلَلَنْ تُفْعَلَ
Third-person fem. dualلَنْ تَفْعَلَالَنْ تُفْعَلَا
Third-person fem. pluralلَنْ يَفْعَلْنَلَنْ يُفْعَلْنَ

The feminine singular takes final fatḥa; the feminine dual loses inflectional nūn, while the feminine plural retains the nūn of women.
لَنْ تَفْعَلَ — she will not do.
لَنْ يَفْعَلْنَ — the women will not do.
The feminine third-person plural begins with ي, unlike the second-person feminine plural, which begins with ت.

10. Lan: masculine second-person paradigm

Lan: active | passive

FormActivePassive
Second-person masc. singularلَنْ تَفْعَلَلَنْ تُفْعَلَ
Second-person masc. dualلَنْ تَفْعَلَالَنْ تُفْعَلَا
Second-person masc. pluralلَنْ تَفْعَلُوالَنْ تُفْعَلُوا

لَنْ تَفْعَلَ means ‘you (one male) will not do’. In the dual and plural, the alif or wāw remains while inflectional nūn drops.
لَنْ تَفْعَلَا — you two will not do.
لَنْ تَفْعَلُوا — you (masc. plural) will not do.
All these are future-negative statements; they are not imperatives or prohibitions.

11. Lan: feminine second-person paradigm

Lan: active | passive

FormActivePassive
Second-person fem. singularلَنْ تَفْعَلِيلَنْ تُفْعَلِي
Second-person fem. dualلَنْ تَفْعَلَالَنْ تُفْعَلَا
Second-person fem. pluralلَنْ تَفْعَلْنَلَنْ تُفْعَلْنَ

The feminine singular تَفْعَلِينَ loses its inflectional nūn, becoming تَفْعَلِي. The feminine dual likewise loses it; the feminine plural retains nūn al-niswah.
لَنْ تَفْعَلِي — you, one woman, will not do.
لَنْ تَفْعَلْنَ — you women will not do.
The different endings ي and نَ identify different persons.

12. Lan: first-person singular and plural

Lan: active | passive
First-person singular — لَنْ أَفْعَلَ | لَنْ أُفْعَلَ
First-person plural — لَنْ نَفْعَلَ | لَنْ نُفْعَلَ
أَفْعَلُ refers to ‘I’ and نَفْعَلُ to ‘we’. Both normally end in indicative ḍamma, changed to subjunctive fatḥa after lan.
لَنْ أَفْعَلَ — I will not do.
لَنْ نَفْعَلَ — we will not do.
The passive forms لَنْ أُفْعَلَ and لَنْ نُفْعَلَ instead deny that an action will be done to me or to us.

13. What the complete lan paradigm establishes

The full fourteen-form active paradigm and fourteen-form passive paradigm follow the same rule under lan.

Word / formMeaning / explanation
5 positionsfinal ḍamma becomes fatḥa: يَفْعَلُ ← لَنْ يَفْعَلَ.
7 positionsinflectional nūn is dropped: تَفْعَلِينَ ← لَنْ تَفْعَلِي.
2 positionsfeminine-plural nūn stays: يَفْعَلْنَ ← لَنْ يَفْعَلْنَ.

Thus 5 + 7 + 2 = 14 paradigm positions are covered. These are counts of grammatical positions, not necessarily distinct written forms.

14. Lam governs the jussive

Lam negates an imperfect verb but transfers the meaning to past time. The verb following lam is jussive (majzūm).
يَفْعَلُ ← لَمْ يَفْعَلْ — he did not do.
يُفْعَلُ ← لَمْ يُفْعَلْ — it was not done to him/it.
Compare لَنْ يَفْعَلَ (final fatḥa) with لَمْ يَفْعَلْ (final sukūn); the two must not be pronounced alike.
Although the verb is morphologically imperfect, lam makes the complete construction past-negative.

15. Lam changes final ḍamma to sukūn

In the five positions where the indicative imperfect has final ḍamma, lam replaces it with sukūn.

Word / formMeaning / explanation
يَفْعَلُ ← لَمْ يَفْعَلْhe did not do.
تَفْعَلُ ← لَمْ تَفْعَلْyou (masc.) did not do, or she did not do.
أَفْعَلُ ← لَمْ أَفْعَلْI did not do.
نَفْعَلُ ← لَمْ نَفْعَلْwe did not do.

The same positions take fatḥa after lan but sukūn after lam: the essential difference between subjunctive and jussive here.

16. Nūn deletion after lam

The same seven positions lose the inflectional nūn after lam as they do after lan.

Word / formMeaning / explanation
يَفْعَلَانِ ← لَمْ يَفْعَلَاthe two did not do.
تَفْعَلُونَ ← لَمْ تَفْعَلُواyou (masc. plural) did not do.
تَفْعَلِينَ ← لَمْ تَفْعَلِيyou (one woman) did not do.

The resulting endings after lan and lam look the same in these positions; the initial particle and its temporal meaning distinguish the constructions.

17. Lam and the retained feminine-plural nūn

The third-person and second-person feminine plurals end in nūn al-niswah. These forms are already indeclinable (mabnī), so lam does not remove their final nūn.
لَمْ يَفْعَلْنَ — those women did not do.
لَمْ تَفْعَلْنَ — you women did not do.
Contrast لَمْ يَفْعَلُوا, where the masculine-plural inflectional nūn is deleted.
Here the jussive is the grammatical status imposed by the particle; an indeclinable form can occupy that position without a visible change to its ending.

18. Lam with passive imperfect verbs

Lam also governs the jussive in passive imperfect forms. The final indicative ḍamma becomes sukūn, or an inflectional nūn is dropped, depending on the position.

Word / formMeaning / explanation
يُفْعَلُ ← لَمْ يُفْعَلْit was not done to him/it.
تُفْعَلِينَ ← لَمْ تُفْعَلِيit was not done to you (one woman).
نُفْعَلُ ← لَمْ نُفْعَلْit was not done to us.

The passive template is identified by the ḍamma on the initial imperfect prefix; lam changes the ending. Replacing it with an active form or ordinary perfect verb would fail to reproduce this paradigm.

19. Lam: masculine third-person paradigm

Lam: active | passive

FormActivePassive
Third-person masc. singularلَمْ يَفْعَلْلَمْ يُفْعَلْ
Third-person masc. dualلَمْ يَفْعَلَالَمْ يُفْعَلَا
Third-person masc. pluralلَمْ يَفْعَلُوالَمْ يُفْعَلُوا

The singular ends in sukūn; the dual and plural lose their inflectional nūn.

Word / formMeaning / explanation
لَمْ يَفْعَلْhe did not do.
لَمْ يَفْعَلَاthe two males did not do.
لَمْ يُفْعَلُواit was not done to those males.

The verbal form remains imperfect, but its meaning is past-negative.

20. Lam: feminine third-person paradigm

Lam: active | passive

FormActivePassive
Third-person fem. singularلَمْ تَفْعَلْلَمْ تُفْعَلْ
Third-person fem. dualلَمْ تَفْعَلَالَمْ تُفْعَلَا
Third-person fem. pluralلَمْ يَفْعَلْنَلَمْ يُفْعَلْنَ

The feminine singular is لَمْ تَفْعَلْ, while the feminine dual is لَمْ تَفْعَلَا. The feminine-plural nūn remains unchanged.
لَمْ يَفْعَلْنَ — those women did not do.
لَمْ يُفْعَلْنَ — it was not done to those women.
The visible shape تَفْعَلْ can be either third-person feminine singular or second-person masculine singular; context settles the reading.

21. Lam: masculine second-person paradigm

Lam: active | passive

FormActivePassive
Second-person masc. singularلَمْ تَفْعَلْلَمْ تُفْعَلْ
Second-person masc. dualلَمْ تَفْعَلَالَمْ تُفْعَلَا
Second-person masc. pluralلَمْ تَفْعَلُوالَمْ تُفْعَلُوا

The second-person masculine singular has a final sukūn, while the dual and plural show deletion of inflectional nūn.

Word / formMeaning / explanation
لَمْ تَفْعَلْyou (one male) did not do.
لَمْ تَفْعَلَاyou two did not do.
لَمْ تَفْعَلُواyou (masc. plural) did not do.

In the passive, the person addressed remains the subject but is described as the person acted upon.

22. Lam: feminine second-person paradigm

Lam: active | passive

FormActivePassive
Second-person fem. singularلَمْ تَفْعَلِيلَمْ تُفْعَلِي
Second-person fem. dualلَمْ تَفْعَلَالَمْ تُفْعَلَا
Second-person fem. pluralلَمْ تَفْعَلْنَلَمْ تُفْعَلْنَ

The second-person feminine singular تَفْعَلِينَ becomes لَمْ تَفْعَلِي, losing inflectional nūn while keeping yāʾ. The feminine dual loses nūn as well, but the feminine plural keeps its own nūn.
لَمْ تَفْعَلِي — you (one woman) did not do.
لَمْ تَفْعَلْنَ — you women did not do.
Both constructions negate a past action despite using imperfect prefixes.

23. Lam: first-person singular and plural

Lam: active | passive
First-person singular — لَمْ أَفْعَلْ | لَمْ أُفْعَلْ
First-person plural — لَمْ نَفْعَلْ | لَمْ نُفْعَلْ
First-person singular has the initial أ, and first-person plural has ن. After lam, both take final sukūn.

Word / formMeaning / explanation
لَمْ أَفْعَلْI did not do.
لَمْ نَفْعَلْwe did not do.
لَمْ أُفْعَلْit was not done to me.
لَمْ نُفْعَلْit was not done to us.

The prefix and its vowel distinguish person and active/passive voice.

24. Distinguishing lā, lan and lam

Using the same verb shows the distinction between the earlier lā and this lesson's lan and lam.

Word / formMeaning / explanation
لَا يَكْتُبُhe does not write (or, contextually, will not write).
لَنْ يَكْتُبَhe will not write; future negative with final fatḥa.
لَمْ يَكْتُبْhe did not write; past negative with final sukūn.
لَا يَكْتُبُونَthey do not write.
لَنْ يَكْتُبُوا / لَمْ يَكْتُبُواboth lose the nūn, but the first denies future action and the second denies past action.

25. Applying the rules to the textbook exercises

The exercise on printed page 19 includes forms such as لَنْ يَجْتَنِبَ، لَنْ يَسْمَعَ، لَمْ يَكْتُبْ، لَمْ يَعْلَمْ for identifying meaning and grammatical person.

Word / formMeaning / explanation
لَنْ يَجْتَنِبَhe will not avoid; third-person masculine singular, future negative.
لَنْ يَسْمَعَhe will not hear; third-person masculine singular, future negative.
لَمْ يَكْتُبْhe did not write; third-person masculine singular, past negative.
لَمْ يَعْلَمْhe did not know; third-person masculine singular, past negative.

These verbs differ in roots and patterns, but the focus here is how lan/lam affect the imperfect ending.