لم and لمّا with the Jussive | Arabic (Modern Standard) Grammar

Both لم and negative لمّا govern the jussive imperfect, but they do not make the same discourse commitment. لم يصل التقرير says that the report did not arrive in the relevant past period. لمّا يصل التقرير says that it has not arrived yet up to the reference point, normally leaving its later arrival open or expected.

English hides an important structural fact: Arabic uses an imperfect form after these particles even though the clause is interpreted in the past or as “not yet.” Mood is local syntax, while the particle contributes temporal negation. A sound singular has sukūn, a five-verb form loses nūn, and a final-weak verb normally loses its weak letter.

The mood overview maps indicative, subjunctive, and jussive endings. This page develops the semantic contrast between the two negative governors.

The core contrast

Particle	Core meaning	Typical discourse effect	Following form
لَمْ	did not	denies occurrence in a relevant past interval	jussive imperfect
لَمَّا	has/had not yet	reaches a reference point while the expected event remains unrealized	jussive imperfect

لم يصل التقرير إلى اللجنة أمس.

lam yaṣili t-taqrīru ʾilā l-lajnati ʾams.

The report did not reach the committee yesterday.

Underlying jussive يصلْ gains support i before the sun-letter article. أمس closes the relevant past interval; the sentence alone says nothing about whether the report arrived today.

لما يصل التقرير بعد، وما زالت اللجنة تنتظره.

lammā yaṣili t-taqrīru baʿdu, wa-mā zālati l-lajnatu tantaẓiruh.

The report has not arrived yet, and the committee is still waiting for it.

بعدُ reinforces “yet,” but لمّا already contains that not-yet perspective. The continued waiting makes the open expectation especially clear. لم + jussive + بعدُ can also mean “not yet”; in that alternative, بعدُ contributes the open boundary, whereas لمّا packages it in the negative particle itself.

لم تحضر الطبيبة جلسة الاثنين بسبب المرض.

lam taḥḍuri ṭ-ṭabībatu jalsata l-ithnayni bi-sababi l-maraḍ.

The doctor did not attend Monday's session because of illness. (Female.)

لما تصل الطبيبة، لذلك أبقينا موعدها مفتوحا.

lammā taṣili ṭ-ṭabībatu, li-dhālika ʾabqaynā mawʿidahā maftūḥan.

The doctor has not arrived yet, so we have kept her appointment open.

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Use لمّا when “up to now/then” matters. Use لم when you simply deny an event in a past frame. Adding بعد can emphasize “yet,” but does not create the contrast by itself.

Jussive morphology after both particles

The two particles govern exactly the same mood morphology.

Agreement/stem	Indicative	After لم	After لمّا
sound singular	يَكْتُبُ	لَمْ يَكْتُبْ	لَمَّا يَكْتُبْ
dual	يُرَاجِعَانِ	لَمْ يُرَاجِعَا	لَمَّا يُرَاجِعَا
masculine plural	يُرْسِلُونَ	لَمْ يُرْسِلُوا	لَمَّا يُرْسِلُوا
feminine plural	يُرْسِلْنَ	لَمْ يُرْسِلْنَ	لَمَّا يُرْسِلْنَ

The feminine-plural nūn is an agreement suffix and remains. The nūn of dual, masculine-plural, and feminine-singular five-verb forms is the indicative marker and disappears.

الباحثتان لم تنتهيا من تحليل العينة أمس.

ʾal-bāḥithatāni lam tantahiyā min taḥlīli l-ʿayyinati ʾams.

The two researchers did not finish analyzing the sample yesterday. (Both female.)

الباحثتان لما تنتهيا من التحليل، لكنهما تتوقعان إنهاءه قريبا.

ʾal-bāḥithatāni lammā tantahiyā mina t-taḥlīli, lakinnahumā tatawaqqaʿāni ʾinhāʾahu qarīban.

The two researchers have not finished the analysis yet, but they expect to finish it soon. (Both female.)

Form VIII اِنْتَهَى / يَنْتَهِي, root ن ه ي, has dual jussive تنتهيا through nūn deletion. The weak yāʾ is part of the dual form and remains before alif; this is not the singular لم ينتهِ pattern.

الموظفات لما يرسلن النسخة النهائية لأن المراجعة مستمرة.

ʾal-muwaẓẓafātu lammā yursilna n-nuskhata n-nihāʾiyyata li-ʾanna l-murājaʿata mustamirra(h).

The employees have not sent the final version yet because the review is continuing. (All female.)

Invariant يرسلنَ still has jussive syntax even though no segment changes.

Weak-final verbs show deletion

Final-weak verbs reveal the jussive strongly:

Principal parts	Indicative	Jussive
دَعَا / يَدْعُو; root د ع و	يَدْعُو	لَمْ يَدْعُ
رَمَى / يَرْمِي; root ر م ي	يَرْمِي	لَمْ يَرْمِ
سَعَى / يَسْعَى; root س ع ي	يَسْعَى	لَمْ يَسْعَ

لم يدع المنظم أي متحدث إضافي إلى الندوة.

lam yadʿu l-munaẓẓimu ʾayya mutaḥaddithin ʾiḍāfiyyin ʾilā n-nadwa(h).

The organizer did not invite any additional speaker to the seminar.

لما يرم الفريق المواد التالفة، فهو ينتظر تعليمات السلامة.

lammā yarmi l-farīqu l-mawādda t-tālifata, fa-huwa yantaẓiru taʿlīmāti s-salāma(h).

The team has not discarded the damaged materials yet; it is waiting for the safety instructions.

لم يسع المدير إلى تمديد العقد بعد رفض الشروط.

lam yasʿa l-mudīru ʾilā tamdīdi l-ʿaqdi baʿda rafḍi sh-shurūṭ.

The director did not seek to extend the contract after the terms were rejected.

Do not retain و، ي، ى by analogy with the indicative. Conversely, dual and plural suffixes can preserve or replace material, so identify the whole agreement cell before deleting anything.

Geminate jussives

Geminate رَدَّ / يَرُدُّ, root ر د د, permits contracted jussive يردَّ in connected pronunciation, alongside expanded يردُدْ. The final fatḥa in the contracted form resolves the impossible consonant cluster; it does not make the verb subjunctive.

لم يرد المدير على الرسالة لأنه كان خارج المكتب.

lam yarudda l-mudīru ʿalā r-risālati li-ʾannahu kāna khārija l-maktab.

The director did not reply to the message because he was out of the office.

Governor لم establishes the jussive despite the surface resemblance to subjunctive لن يردَّ.

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With weak and geminate verbs, never identify mood from one final letter or vowel alone. Start with لم/لمّا, then retrieve the verified jussive cell for that root class and agreement form.

The “not yet” implication is strong but not a promise

Negative لمّا normally directs attention to a boundary: the event has failed to occur up to now or up to some past point. Speakers often expect it later, but grammar does not guarantee fulfillment.

لما يصل الرد، ويبدو الآن أنه لن يصل هذا الأسبوع.

lammā yaṣili r-raddu, wa-yabdū l-ʾāna ʾannahu lan yaṣila hādhā l-ʾusbūʿ.

The reply has not arrived yet, and it now appears that it will not arrive this week.

The second clause weakens the expectation without contradicting the grammatical “not yet” boundary.

Do not confuse negative لمّا + jussive with temporal لمّا “when,” which commonly introduces a perfect clause: لمّا وصل المدير بدأ الاجتماع “When the director arrived, the meeting began.” Unvocalized spelling is the same; the following verb form and context disambiguate it.

Common Mistakes

Placing a perfect directly after لم

❌ لم وصل التقرير إلى القسم.

Incorrect — لم requires a jussive imperfect, not perfect وصل.

✅ لم يصل التقرير إلى القسم قبل إغلاق المكتب.

lam yaṣili t-taqrīru ʾilā l-qismi qabla ʾighlāqi l-maktab.

The report did not reach the department before the office closed.

Pronouncing a sound singular as indicative

❌ لم يكتب المحرر الملاحظة.

lam yaktubu l-muḥarriru l-mulāḥaẓa

Incorrect pronunciation — لم governs jussive يكتبْ, with a support vowel only if the next cluster requires it.

✅ لم يكتب المحرر الملاحظة في النسخة الأولى.

lam yaktubi l-muḥarriru l-mulāḥaẓata fī n-nuskhati l-ʾūlā.

The editor did not write the note in the first version.

Retaining nūn in a dual jussive

❌ الباحثتان لم تنتهيان من التحليل.

Incorrect — dual تنتهيان loses nūn after لم.

✅ الباحثتان لم تنتهيا من تحليل التسجيلات.

ʾal-bāḥithatāni lam tantahiyā min taḥlīli t-tasjīlāt.

The two researchers did not finish analyzing the recordings. (Both female.)

Keeping the final weak letter

❌ لم يدعو المنظم ضيوفا آخرين.

Incorrect — singular يدعو loses final wāw in the jussive: لم يدعُ.

✅ لم يدع المنظم ضيوفا آخرين بسبب ضيق القاعة.

lam yadʿu l-munaẓẓimu ḍuyūfan ʾākharīna bi-sababi ḍīqi l-qāʿa(h).

The organizer did not invite additional guests because the hall was too small.

Key Takeaways

لم + jussive negates occurrence in a relevant past interval.
لمّا + jussive means “not yet” up to a present or past reference point.
The not-yet construction suggests an open expectation but does not guarantee later fulfillment.
Both particles trigger the same morphology: sukūn, nūn deletion, or final-weak deletion as appropriate.
Temporal لمّا “when” is a separate construction, commonly followed by a perfect verb.

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