Emphatic Lām and the Heavy and Light Nūn Paradigms

1. Emphatic lām and certainty about the future

The imperfect can refer to an action in the present or future. To assert a future action with particular force, Arabic can put an emphatic lām before the imperfect and an emphatic nūn at its end.
يَفْعَلُ — he does or will do.
لَيَفْعَلَنَّ — he will certainly do it.
The second form does more than locate the event in the future: it strengthens the assertion. The initial lām and the final nūn work together, and the chapter forms both active and passive conjugations on this basis.

2. Two forms of the emphatic nūn

There are two kinds of emphatic nūn. The heavy nūn (thaqīlah) carries a shaddah; the light nūn (khafīfah) is a sākin nūn without shaddah.
لَيَفْعَلَنَّ — heavy nūn: he will certainly do it.
لَيَفْعَلَنْ — light nūn: he will certainly do it.
Both emphasise, but their morphology differs. The heavy-nūn table has forms in all fourteen person positions; the light-nūn table deliberately omits six positions. They are not freely interchangeable everywhere.

3. How the prefix and suffix work together

A general formation rule is to prefix لَـ to the active or passive imperfect, remove any applicable indicative inflectional nūn, and attach an emphatic nūn. The person endings are not treated identically in every form.
يَفْعَلُ ← لَيَفْعَلَنَّ — he will certainly do it.
تُفْعَلُ ← لَتُفْعَلَنَّ — it will certainly be done to her.
The first example is active and the second passive. Emphasis is present in both, while the internal vowel pattern continues to distinguish the voices.

4. Singular and first-person endings

In the simple singular and first-person positions, the heavy nūn is generally preceded by a fatḥa. The normal indicative final ḍamma does not remain before the emphatic ending.

Word / formMeaning / explanation
يَفْعَلُ ← لَيَفْعَلَنَّhe will certainly do.
تَفْعَلُ ← لَتَفْعَلَنَّyou (masc.) will certainly do, or she will certainly do.
أَفْعَلُ ← لَأَفْعَلَنَّI will certainly do.
نَفْعَلُ ← لَنَفْعَلَنَّwe will certainly do.

Person remains crucial even when several forms look alike at their ends.

5. Dual forms retain the alif

Ordinary dual imperfect forms have an alif followed by an indicative inflectional nūn. With heavy emphasis, that inflectional nūn disappears and a heavy nūn with kasrah follows the retained alif.
يَفْعَلَانِ ← لَيَفْعَلَانِّ — the two males will certainly do.
تَفْعَلَانِ ← لَتَفْعَلَانِّ — the two females will certainly do, or you two will certainly do.
Retaining the alif preserves dual number. The textbook's light-nūn column has dashes for these dual positions, so do not invent a parallel light form.

6. The masculine plural loses its wāw

In يَفْعَلُونَ and تَفْعَلُونَ, the wāw signals masculine plural and the nūn is the indicative inflectional ending. Before the emphatic nūn, both the inflectional nūn and the plural wāw disappear, but the ḍamma before the emphatic ending preserves the plural distinction.
يَفْعَلُونَ ← لَيَفْعَلُنَّ — the men will certainly do.
تَفْعَلُونَ ← لَتَفْعَلُنَّ — you men will certainly do.
Compare singular لَيَفْعَلَنَّ: the singular has fatḥa before the nūn, while the masculine plural has ḍamma.

7. Second-person feminine singular takes kasrah

The second-person feminine singular imperfect is تَفْعَلِينَ. Its yāʾ and inflectional nūn drop before heavy emphasis, while the kasrah immediately before the heavy nūn remains.
تَفْعَلِينَ ← لَتَفْعَلِنَّ — you (one woman) will certainly do.
Compare لَتَفْعَلَنَّ addressed to one man. The prefix is the same, but the kasrah versus fatḥa before the emphatic nūn distinguishes the addressee's gender. This vowel matters in accurate translation.

8. The separating alif in feminine plural forms

The nūn al-niswah identifying the feminine plural is retained. Adjacent use of the heavy emphatic nūn would be awkward, so a separating alif (alif fāṣil) is inserted between the two nūns.
يَفْعَلْنَ ← لَيَفْعَلْنَانِّ — those women will certainly do.
تَفْعَلْنَ ← لَتَفْعَلْنَانِّ — you women will certainly do.
The first nūn marks feminine plural person; the last, doubled nūn marks emphasis. The textbook provides no light-nūn forms for these two positions.

9. Heavy nūn: third-person masculine forms

In the active heavy-nūn paradigm, the three masculine third-person positions are:

Word / formMeaning / explanation
لَيَفْعَلَنَّthird masculine singular
لَيَفْعَلَانِّthird masculine dual
لَيَفْعَلُنَّthird masculine plural

The singular has fatḥa before the nūn, the dual retains the alif and has a kasrah on the doubled nūn, and the masculine plural has ḍamma immediately before it.
One man will certainly do; two men will certainly do; the men will certainly do. All three begin with third-person yāʾ, so the ending identifies their number.

10. Heavy nūn: third-person feminine forms

Active feminine third-person positions with the heavy emphatic nūn are:

Word / formMeaning / explanation
لَتَفْعَلَنَّthird feminine singular
لَتَفْعَلَانِّthird feminine dual
لَيَفْعَلْنَانِّthird feminine plural

They mean, respectively: she will certainly do, the two women will certainly do, and the women will certainly do. The feminine plural here begins with yāʾ, unlike the feminine singular and dual forms that begin with tāʾ. The feminine plural additionally preserves the feminine nūn and inserts alif fāṣil before the doubled emphatic nūn.

11. Heavy nūn: second-person masculine forms

The active masculine second-person heavy-nūn positions are:

Word / formMeaning / explanation
لَتَفْعَلَنَّsecond masculine singular
لَتَفْعَلَانِّsecond masculine dual
لَتَفْعَلُنَّsecond masculine plural

They mean: you (one man), you (two men), and you (men) will certainly do it. The second-person prefix tāʾ remains. A fatḥa before the emphatic nūn marks singular, a retained alif marks dual, and the preceding ḍamma identifies masculine plural.

12. Heavy nūn: second-person feminine forms

Active feminine second-person heavy-nūn positions are:

Word / formMeaning / explanation
لَتَفْعَلِنَّsecond feminine singular
لَتَفْعَلَانِّsecond feminine dual
لَتَفْعَلْنَانِّsecond feminine plural

They mean: you (one woman), you (two women), and you (women) will certainly do. The feminine singular is marked by a kasrah immediately before the heavy nūn. The feminine plural retains nūn al-niswah and takes a separating alif, unlike the masculine plural's ḍamma ending.

13. Heavy nūn: first-person forms

First-person active forms are distinguished by their prefixes:

Word / formMeaning / explanation
لَأَفْعَلَنَّfirst person singular
لَنَفْعَلَنَّfirst person plural
لَأَفْعَلَنَّI will certainly do.
لَنَفْعَلَنَّwe will certainly do.

After the emphatic lām, أَ marks first-person singular while نَ marks first-person plural. Both have fatḥa before the heavy nūn, so the prefix is decisive.

14. Emphasis leaves the active/passive distinction intact

A passive imperfect has ḍamma on the imperfect prefix and the basic pattern يُفْعَلُ. Adding emphatic nūn does not turn the passive voice into active voice.

Word / formMeaning / explanation
لَيَفْعَلَنَّhe will certainly act (active).
لَيُفْعَلَنَّthe action will certainly be done to him (passive).
لَتَفْعَلِنَّyou, one woman, will certainly act (active).
لَتُفْعَلِنَّthe action will certainly be done to you (passive).

The grammatical participant changes, but the emphatic meaning remains.

15. Heavy passive: all six third-person positions

These are the six third-person passive heavy-nūn positions:

Word / formMeaning / explanation
لَيُفْعَلَنَّthird masculine singular
لَيُفْعَلَانِّthird masculine dual
لَيُفْعَلُنَّthird masculine plural
لَتُفْعَلَنَّthird feminine singular
لَتُفْعَلَانِّthird feminine dual
لَيُفْعَلْنَانِّthird feminine plural

They cover masculine singular/dual/plural and feminine singular/dual/plural. The ḍamma of the passive prefix remains. The same rules of masculine plural wāw deletion, dual alif retention, and feminine-plural separating alif continue to apply.

16. Heavy passive: all six second-person positions

These are the six second-person passive heavy-nūn positions:

Word / formMeaning / explanation
لَتُفْعَلَنَّsecond masculine singular
لَتُفْعَلَانِّsecond masculine dual
لَتُفْعَلُنَّsecond masculine plural
لَتُفْعَلِنَّsecond feminine singular
لَتُفْعَلَانِّsecond feminine dual
لَتُفْعَلْنَانِّsecond feminine plural

لَتُفْعَلَنَّ refers to one male addressee, while لَتُفْعَلِنَّ addresses one woman. Both are passive; fatḥa versus kasrah before the heavy nūn differentiates them. The other forms preserve the relevant distinctions of number and gender.

17. Heavy passive: first-person singular and plural

The first-person passive heavy-nūn forms are:

Word / formMeaning / explanation
لَأُفْعَلَنَّfirst person singular
لَنُفْعَلَنَّfirst person plural
لَأُفْعَلَنَّsomething will certainly be done to me.
لَنُفْعَلَنَّsomething will certainly be done to us.

Compare the active forms لَأَفْعَلَنَّ and لَنَفْعَلَنَّ. Passive vowel patterns change the voice, while the emphatic nūn gives the same force to the assertion.

18. The light emphatic nūn is sākin

The light emphatic nūn is sākin rather than doubled. Both forms still express emphasis; removing the shaddah does not turn the construction into an ordinary un-emphasised imperfect.

Word / formMeaning / explanation
لَيَفْعَلَنَّ ← لَيَفْعَلَنْhe will certainly do it.
لَيُفْعَلَنَّ ← لَيُفْعَلَنْit will certainly be done to him.
لَأَفْعَلَنَّ ← لَأَفْعَلَنْI will certainly do it.

But this substitution is not permitted in all fourteen positions. The six positions left blank by the textbook must remain blank.

19. Only eight positions accept the light nūn

Only eight of the fourteen positions accept the light emphatic nūn: third masculine singular and plural, third feminine singular, second masculine singular and plural, second feminine singular, and both first-person positions.
Not given: the four dual positions and the two feminine-plural positions. These six omissions apply equally to the active and passive light-nūn columns. The textbook marks them with dashes; they are not to be filled with invented forms.

20. Light active: third-person forms

These are all six third-person positions in the active light-nūn table:
لَيَفْعَلَنْ — third masculine singular
— — third masculine dual (not given in the source paradigm)
لَيَفْعَلُنْ — third masculine plural
لَتَفْعَلَنْ — third feminine singular
— — third feminine dual (not given in the source paradigm)
— — third feminine plural (not given in the source paradigm)
Only masculine singular, masculine plural and feminine singular have forms here. The two dual forms and feminine plural are intentionally absent. In لَيَفْعَلَنْ, the nūn is sākin; in لَيَفْعَلُنْ, the preceding ḍamma continues to distinguish the masculine plural.

21. Light active: second- and first-person forms

The remaining eight positions in the active light-nūn table are:
لَتَفْعَلَنْ — second masculine singular
— — second masculine dual (not given in the source paradigm)
لَتَفْعَلُنْ — second masculine plural
لَتَفْعَلِنْ — second feminine singular
— — second feminine dual (not given in the source paradigm)
— — second feminine plural (not given in the source paradigm)
لَأَفْعَلَنْ — first person singular
لَنَفْعَلَنْ — first person plural
The second-person masculine singular has fatḥa before the sākin nūn; masculine plural has ḍamma; feminine singular has kasrah. Both first-person forms have fatḥa before the nūn, while their initial alif and nūn indicate “I” versus “we.”

22. Light passive: third-person forms

The passive light-nūn third-person positions are:
لَيُفْعَلَنْ — third masculine singular
— — third masculine dual (not given in the source paradigm)
لَيُفْعَلُنْ — third masculine plural
لَتُفْعَلَنْ — third feminine singular
— — third feminine dual (not given in the source paradigm)
— — third feminine plural (not given in the source paradigm)
The supplied forms refer to masculine singular, masculine plural and feminine singular recipients of the action. The other three slots remain unfilled. A light nūn's being sākin does not make every heavy-nūn form eligible for a corresponding light form.

23. Light passive: second- and first-person forms

These are the passive light-nūn second- and first-person positions:
لَتُفْعَلَنْ — second masculine singular
— — second masculine dual (not given in the source paradigm)
لَتُفْعَلُنْ — second masculine plural
لَتُفْعَلِنْ — second feminine singular
— — second feminine dual (not given in the source paradigm)
— — second feminine plural (not given in the source paradigm)
لَأُفْعَلَنْ — first person singular
لَنُفْعَلَنْ — first person plural
لَتُفْعَلِنْ refers to one female addressee in the passive, whereas لَتُفْعَلُنْ refers to male plural addressees.
لَأُفْعَلَنْ — it will certainly be done to me.
لَنُفْعَلَنْ — it will certainly be done to us.
The initial ḍamma identifies passive voice and the final sākin nūn identifies light emphasis.

24. Identical surface forms and their grammatical positions

A single written form may occupy more than one grammatical person slot. Consequently, the form alone does not always uniquely determine the subject.
لَتَفْعَلَنَّ can mean third-person feminine singular or second-person masculine singular.
لَتَفْعَلَانِّ can be third-person feminine dual or either second-person dual.
لَتُفْعَلَنَّ shows the corresponding passive ambiguity in the singular.
The pronoun, relationship to the subject or passive subject, and sentence context determine the intended reading.

25. Applying the rule to real verbal roots

The textbook's practice verbs can be used to apply the same morphological operation. These are active, masculine third-person singular examples with heavy emphasis:

Word / formMeaning / explanation
يَجْتَنِبُ ← لَيَجْتَنِبَنَّhe will certainly avoid.
يَسْمَعُ ← لَيَسْمَعَنَّhe will certainly hear.
يَتْرُكُ ← لَيَتْرُكَنَّhe will certainly leave.
يَكْتُبُ ← لَيَكْتُبَنَّhe will certainly write.

The root letters remain; the emphatic lām and doubled nūn are added, and the ordinary final ḍamma gives way to fatḥa.