لم and لمّا | Arabic (Modern Standard) Grammar

Formal Modern Standard Arabic uses لم before a jussive imperfect to deny a past event: لم يكتبْ means “he did not write.” Closely related لمّا also governs the jussive, but means “not yet”: the event has not happened up to the relevant reference point and is still presented as pending. English uses did not or has not yet; Arabic packages time, polarity, and verbal mood into one small particle.

This page treats the particles as pieces of clause structure: where they stand, what falls inside their scope, and how their grammatical effect stops at a clause boundary. For the complete verb-class inventory, see past negation with لم.

One particle, two grammatical instructions

لم is an independent word written separately from the imperfect. It does two jobs at once:

it places the denied situation before the reference time; and
it governs the following imperfect in the jussive.

With sound singular يكتبُ, jussive mood appears as final sukūn: لم يكتبْ. The subject and object retain the cases required by their own roles; لم changes the verb’s mood, not a noun’s case.

كتب المحرر الخبر صباحا

kataba l-muḥarriru l-khabara ṣabāḥan

The editor wrote the report in the morning. (Affirmative perfect.)

لم يكتب المحرر الخبر صباحا

lam yaktubi l-muḥarriru l-khabara ṣabāḥan

The editor did not write the report in the morning. (لم plus jussive imperfect.)

The connected reading يكتبِ المحرر contains a helping kasra before the article’s elided hamzat al-waṣl. The underlying governed form is still يكتبْ. This is pronunciation at a word boundary, not a return to the indicative يكتبُ.

💡

Do not search for an Arabic equivalent of English did. Read the Arabic construction as a package: لم supplies past negation, while the imperfect supplies the event and agreement and appears in the jussive.

The jussive is not always a visible sukūn

The form after لم depends on the verb’s agreement class and stem. Sound singulars take sukūn; the “five verbs” lose their mood nūn; final-weak singulars delete the final weak letter. Feminine-plural ـنَ remains because it marks the subject, not mood.

Indicative	After لم	Visible effect
يَكْتُبُ	لَمْ يَكْتُبْ	final sukūn
يَكْتُبُونَ	لَمْ يَكْتُبُوا	mood nūn deleted
تَكْتُبِينَ	لَمْ تَكْتُبِي	mood nūn deleted
يَدْعُو	لَمْ يَدْعُ	final weak letter deleted
يَسْعَى	لَمْ يَسْعَ	final weak letter deleted
يَكْتُبْنَ	لَمْ يَكْتُبْنَ	feminine-plural nūn retained

الوفدان لم يقدما اقتراحا مشتركا

al-wafdāni lam yuqaddimā qtirāḥan mushtarakan

The two delegations did not submit a joint proposal. (The dual loses mood nūn.)

لم يدع المتحدث إلى تغيير الخطة

lam yadʿu l-mutaḥaddithu ʾilā taghyīri l-khuṭṭa(h)

The spokesperson did not call for changing the plan. (Final و is deleted.)

الباحثات لم يهملن النتائج المخالفة

al-bāḥithātu lam yuhmilna n-natāʾija l-mukhālifa(h)

The female researchers did not ignore the contrary results. (Feminine-plural nūn remains.)

The spelling of an unvocalized form can hide the mood contrast. لم يكتبان is wrong because dual indicative nūn remains visible, but singular لم يسع must be analyzed as jussive يسعَ, not guessed from the absence of a written short vowel.

لمّا means “not yet”

Negative لمّا is also followed by a jussive imperfect. Unlike plain لم, it explicitly says that the situation has not held up to now or up to another reference point. It commonly carries an expectation that the event may still occur, although context can cancel that expectation.

لم يصل القطار

lam yaṣili l-qiṭār

The train did not arrive / has not arrived. (Plain past negation; context fixes the English tense.)

لما يصل القطار

lammā yaṣili l-qiṭār

The train has not arrived yet. (Arrival remains pending at the reference time.)

This pair is a true scope-and-meaning contrast. لم denies the event in the relevant past interval. لمّا makes the interval extend to the reference point and contributes “not yet.” English often needs an adverb that Arabic builds into the particle.

عندما بدأت الجلسة، لما يكن الخبير قد وصل

ʿindamā badaʾati l-jalsatu, lammā yakuni l-khabīru qad waṣal

When the session began, the expert had not yet arrived.

Here the reference point is the beginning of the session, not the speaker’s present. لمّا can therefore correspond to English had not yet, not only has not yet.

💡

Use لمّا + jussive when “up to that point, not yet” is part of the message. Use لم + jussive for plain past denial. The difference is temporal viewpoint, not formality.

Negative لمّا versus conjunction لمّا

Ordinary unvocalized writing gives both functions the same spelling لما. Syntax distinguishes them:

negative لَمَّا precedes a jussive imperfect and means “not yet”;
temporal لَمَّا introduces a clause, commonly with a perfect, and means “when/once.”

لما ينته التحقيق، ولذلك لم تنشر الصحيفة التفاصيل

lammā yantahi t-taḥqīqu, wa-li-dhālika lam tanshuri ṣ-ṣaḥīfatu t-tafāṣīl

The investigation has not ended yet, so the newspaper has not published the details. (Negative لمّا.)

لما انتهى التحقيق، نشرت الصحيفة التفاصيل

lammā ntahā t-taḥqīqu, nasharati ṣ-ṣaḥīfatu t-tafāṣīl

When the investigation ended, the newspaper published the details. (Temporal conjunction لمّا.)

In the first sentence, final-weak ينتهي becomes jussive ينتهِ. In the second, perfect انتهى is not governed by a negator. Calling every written لما “not yet” would reverse the relation between the two events.

Scope stops at the clause boundary

لم normally stands immediately before the imperfect it governs. A conjunction may attach to the particle—ولم، فلم—but the particle is still separate from its verb. Its negation belongs to its own clause; it does not automatically spread through لكن “but” or into a new finite clause.

لم توافق اللجنة على الاقتراح، لكن الوزير أيده

lam tuwāfiqi l-lajnatu ʿalā l-iqtirāḥi, lakinna l-wazīra ʾayyadahu

The committee did not approve the proposal, but the minister supported it.

Only توافق is inside the scope of لم. The perfect أيده begins an affirmative contrasting clause.

لم يراجع سامر التقرير، بل قرأ الملخص فقط

lam yurājiʿ sāmirun at-taqrīra, bal qaraʾa l-mulakhkhaṣa faqaṭ

Samer did not review the report; he only read the summary.

راجع سامر التقرير، لكنه لم يراجع الملحق

rājaʿa sāmirun at-taqrīra, lakinnahu lam yurājiʿi l-mulḥaq

Samer reviewed the report, but he did not review the appendix.

The contrast shows why “negates the verb” is incomplete. The first لم rejects the review event and corrects it with a different event. In the second, only the appendix falls inside the negative clause.

In news and argument

لم and لمّا are neutral (formal) MSA, especially common in reporting, analysis, academic prose, and prepared speech. They do not sound literary merely because they trigger mood marking.

أفادت الوزارة بأن المفاوضات لم تسفر عن اتفاق، وأن الطرفين لما يحددا موعدا جديدا

ʾafādati l-wizāratu bi-ʾanna l-mufāwaḍāti lam tusfir ʿan ittifāqin, wa-ʾanna ṭ-ṭarafayni lammā yuḥaddidā mawʿidan jadīdan

The ministry reported that the negotiations had not produced an agreement and that the two sides had not yet set a new date.

The first clause reports a negative result. The second presents the scheduling as still unresolved. Both particles govern only the imperfect immediately following them; بأنّ and أنّ independently govern their own accusative nouns.

Common Mistakes

Joining the particle to its verb

❌ لميصدر البيان أمس

Incorrect — لم is a separate word before the jussive imperfect.

✅ لم يصدر البيان أمس

lam yaṣduri l-bayānu ʾams

The statement was not issued yesterday.

Using a perfect after لم

❌ لم وصل الوفد في الموعد

Incorrect — negative لم governs a jussive imperfect, not perfect وصل.

✅ لم يصل الوفد في الموعد

lam yaṣili l-wafdu fī l-mawʿid

The delegation did not arrive on time.

Retaining mood nūn

❌ الموظفون لم يرسلوا التقرير

al-muwaẓẓafūna lam yursilūna t-taqrīr

Incorrect reading — the written form must be read yursilū after لم, with mood nūn deleted.

✅ الموظفون لم يرسلوا التقرير اليومي

al-muwaẓẓafūna lam yursilū t-taqrīra l-yawmiyy

The employees did not send the daily report.

Reading every لما as “not yet”

❌ لما وصل الضيف، لم نرحب به

Incorrect interpretation if intended to mean ‘the guest has not arrived yet’: perfect وصل makes لما a temporal conjunction, ‘when the guest arrived.’

✅ لما يصل الضيف

lammā yaṣili ḍ-ḍayf

The guest has not arrived yet.

Substituting present لا or perfect-negating ما without reanalyzing the verb

❌ لا يكتب التقرير أمس

Incorrect for a completed past denial — present/general لا conflicts with أمس in this intended reading.

✅ لم يكتب التقرير أمس

lam yaktubi t-taqrīra ʾams

He did not write the report yesterday.

💡

When you meet لم، لمّا، ما، لا, identify the particle before parsing the verb. Their English translations overlap, but their Arabic government and time structure do not.

Key Takeaways

لم is written separately and gives a following jussive imperfect past-negative reference.
لمّا + jussive means “not yet” relative to the present or another reference point.
Sound singulars show sukūn, five-verb forms lose mood nūn, and final-weak singulars delete the weak letter.
Temporal لمّا + perfect means “when/once”; it is not a negator.
Negation stops at its clause boundary, while noun case and agreement continue to follow their own rules.

Now practice Arabic

Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.

Start learning Arabic →