In short

Arabic has no separate “command form” to memorize. Everything here is built out of the مَجْزوم you learned in lesson 35. Take the أَنْتَ jussive, knock its prefix off, and you have an order: تَكْتُبْ becomes اُكْتُبْ. Leave the prefix on and put لا in front, and you have a prohibition: لا تَكْتُبْ. Two operations on one form you already own.

The only genuinely new piece of spelling is the little alif that appears at the front of اُكْتُبْ. It is there because Arabic cannot start a word with a vowelless consonant, and it is a هَمْزَةُ الوَصْل - a bare ا, never أ. The lesson ends with the third way of aiming words at a person: يا, the vocative particle. It looks trivial and it hides one real rule, because the name you call takes an ending you will not have seen anywhere else.

The rule

1. The imperative is the jussive minus its prefix. Start from the second person of the مُضارِع مَجْزوم - the very form lesson 35 drilled - and delete the تـ:

تَكْتُبْ -> كْتُبْ / تَجْلِسْ -> جْلِسْ / تُساعِدْ -> ساعِدْ

That is the whole operation. The imperative exists only in the second person, so there are exactly five of them: one for each of أَنْتَ، أَنْتِ، أَنْتُما، أَنْتُمْ، أَنْتُنَّ.

2. If the stem now opens on a sukūn, prop it up with هَمْزَةُ الوَصْل. كْتُبْ is unpronounceable: no Arabic word begins with a vowelless consonant. Arabic solves this by writing a helping alif in front, and that alif is vowelled by a simple echo:

• if the stem vowel of the مُضارِع is a ḍamma, the alif takes a ḍamma: يَكْتُبُ -> اُكْتُبْ، يَدْخُلُ -> اُدْخُلْ، يَنْظُرُ -> اُنْظُرْ
• otherwise (kasra or fatḥa) the alif takes a kasra: يَجْلِسُ -> اِجْلِسْ، يَفْتَحُ -> اِفْتَحْ، يَذْهَبُ -> اِذْهَبْ

Look at the middle radical of the present tense and copy its vowel, or fall back to kasra. اُكْتُبْ has two ḍammas, اِجْلِسْ two kasras, اِفْتَحْ a kasra then a fatḥa - never a ḍamma alif over a fatḥa stem.

3. It is a bare ا, never a ء. This is the single most common written error in the whole topic. اُكْتُبْ is spelled with a plain alif carrying only its vowel mark. Writing أُكْتُبْ turns it into a هَمْزَةُ القَطْع, a different letter with a different behaviour - see the pronunciation guide’s hamza lesson. You can hear the difference the moment another word comes first, because a هَمْزَةُ الوَصْل is simply not pronounced there:

وَاكْتُبْ رَقْمَكَ. / ثُمَّ اجْلِسْ. / وَانْتَظِرْ قَليلًا.

The alif stays on the page and goes silent in the mouth: wa-ktub, not wa-uktub.

4. Some stems need no alif at all. If deleting the prefix leaves a consonant that already carries a vowel, you are finished - nothing is added. That covers the derived verbs whose مُضارِع has a ḍamma prefix or a doubled/lengthened opening:

تُعَلِّمْ -> عَلِّمْ / تُساعِدْ -> ساعِدْ / تَتَعَلَّمْ -> تَعَلَّمْ / تَتَعاوَنْ -> تَعاوَنْ

5. Form IV keeps its هَمْزَةُ القَطْع. One family is the exception to rule 3. Verbs of the أَرْسَلَ / يُرْسِلُ type carry a real hamza as part of the pattern, and it comes back in the imperative with a fatḥa on أ:

يُرْسِلُ -> أَرْسِلْ / يُغْلِقُ -> أَغْلِقْ / يُعْطي -> أَعْطِ

So أَرْسِلْ with أ is right and اُكْتُبْ with ا is right; they are not inconsistent, they are two different hamzas. The longer patterns that open with اِ - اِنْتَظِرْ، اِسْتَمِعْ - work exactly like اُكْتُبْ. The families themselves are lessons 46-48.

6. Five addressees, and the ن that disappears. Because the imperative is the jussive, the endings are the jussive endings: the نونُ الرَّفْعِ of تَكْتُبينَ، تَكْتُبانِ، تَكْتُبونَ is deleted, and the masculine plural ـوا is written with a silent alif after it.

اُكْتُبْ، اُكْتُبي، اُكْتُبا، اُكْتُبوا، اُكْتُبْنَ

The ن in the last one is not the same ن: نونُ النِّسْوَةِ is the subject pronoun “you women” itself, part of the word, and it never drops. That is why اُكْتُبْنَ keeps its ن while اُكْتُبوا loses one.

7. The irregular verbs are shorter, not harder. Whatever the jussive does, the imperative does. Hollow verbs (الأَجْوَف) lose their long vowel: تَقُلْ -> قُلْ، تَكُنْ -> كُنْ، تَبِعْ -> بِعْ، تَنَمْ -> نَمْ. Since the result opens on a vowelled consonant, no alif is added. The long vowel returns as soon as an ending follows: قولي، قولوا، كونوا.

Three very frequent verbs simply drop their initial hamza: أَخَذَ -> خُذْ، أَكَلَ -> كُلْ، أَمَرَ -> مُرْ. Verbs with a weak final radical (النّاقِص) lose it in the jussive and therefore in the imperative: تَمْشِ -> اِمْشِ، تَنْسَ -> اِنْسَ، تَدْعُ -> اُدْعُ. And a doubled verb (المُضَعَّف) keeps its shadda and normally ends on a fatḥa: يَرُدُّ -> رُدَّ، يَعُدُّ -> عُدَّ - رُدِّ and the pulled-apart اُرْدُدْ are also correct (lesson 35), but the fatḥa is the form you will meet.

8. A final sukūn meets الـ. اُكْتُبْ ends in a vowelless consonant. If the next word begins with a هَمْزَةُ الوَصْل - and الـ is one - two silent consonants would collide, so the imperative takes a kasra to break them apart:

أَغْلِقْ + البابَ -> أَغْلِقِ البابَ / قُلْ + الحَقيقَةَ -> قُلِ الحَقيقَةَ

This is the same repair you saw in لَيْسَتِ الغُرْفَةُ (lesson 23). Attached object pronouns are added without any such fuss: اُكْتُبْهُ، خُذْها، ساعِدْني.

9. Prohibition is لا + the jussive. To forbid, you do not negate the imperative - there is no such thing as *لا اُكْتُبْ. You go back to the second-person مُضارِع مَجْزوم and put لا النّاهِيَة in front of it:

لا تَكْتُبْ، لا تَكْتُبي، لا تَكْتُبا، لا تَكْتُبوا، لا تَكْتُبْنَ

The prefix stays, the ن of the plural and feminine forms still drops, and irregular verbs shorten exactly as they do in the positive: لا تَقُلْ، لا تَكُنْ، لا تَنْسَ، لا تَخَفْ.

10. لا النّاهِيَة and لا النّافِيَة differ by one vowel. The same little word لا stands in front of a مُضارِع verb in two completely different jobs, and only the final vowel separates them:

• لا تَكْتُبْ. - jussive, sukūn: “Don’t write.”
• لا تَكْتُبُ. - indicative, ḍamma: “You do not write.”

That is a real ambiguity, not a theoretical one. At a pause the ḍamma is dropped anyway in the pausal form, so the two sound identical when the sentence ends there; and in ordinary unvocalized Arabic both are written لا تكتب. Native readers decide from context, and so will you - a lone لا تدخن on a door is an order, and لا يدخن في المكتب inside a paragraph about office rules is a statement. When you write vocalized Arabic yourself, the vowel is your responsibility.

11. Calling someone: يا + a bare name. The vocative particle is يا, and it is used far more freely than English “O” - it is the normal way to attach a name to what you are saying. A single proper name after it is مَبْنِيٌّ عَلى الضَّمِّ: one ḍamma, and crucially no tanwīn, even though مُحَمَّدٌ carries one when it stands on its own.

يا مُحَمَّدُ / يا فاطِمَةُ / يا سَميرُ

The same ending appears when you address someone by role rather than by name - the النَّكِرَة المَقْصودَة, “a specific one of these”: يا سائِقُ، يا مُهَنْدِسُ، يا أُسْتاذُ. Duals and sound masculine plurals keep the shape they would have in the nominative: يا مُهَنْدِسانِ، يا مُهَنْدِسونَ.

12. If the addressee owns something, it turns accusative. The moment the called word is the first half of an إِضافَة (lesson 20), the ḍamma is gone and the word is مَنْصوب:

يا صاحِبَ البَيْتِ / يا مُديرَ المَدْرَسَةِ / يا أَبا عُمَرَ

يا أَبا عُمَرَ shows it clearly: أَبٌ is one of the five nouns whose accusative is a long ـا, so “father of Umar” is أَبا, not أَبو. A pronoun counts as the second half too, which is why يا أُسْتاذي، يا أُمّي، يا صَديقي are accusative as well - you just cannot see the ending under the ي.

13. يا never meets الـ; use أَيُّها. *يا الطّالِبُ is impossible - the one everyday exception is يا اللهُ. To call any other noun that carries the article, Arabic inserts a buffer word: أَيُّها before a masculine noun, أَيَّتُها before a feminine one, and the noun after it stays مَرْفوع:

يا أَيُّها الطّالِبُ / يا أَيُّها النّاسُ / يا أَيَّتُها الطّالِبَةُ

This is the standard opening of any speech or announcement, and there يا is usually left off altogether: أَيُّها السّادَةُ، أَيُّها الحُضورُ.

14. Not in this lesson. There is a way to command a third person or a “we”: لِـ + jussive, called لامُ الأَمْرِ - لِيَكْتُبْ “let him write”, لِنَذْهَبْ “let’s go”, and after وَ or فَ the lām loses its vowel: وَلْيَكْتُبْ. Recognise it; you do not need to produce it. The names of the endings themselves - why the called name is “built” on a ḍamma rather than simply مَرْفوع - belong to the case system in lesson 40.

Forms & patterns

From the present tense to the command

The five addressees, positive and negative

Irregular verbs worth knowing by heart

Note اِمْشِ against اِمْشي: the masculine singular ends in a bare kasra, and the form with a written ي is the one you say to a woman. The dual and the أَنْتُنَّ column are left out here only to keep the table readable; they are built from the jussive like everything else (اِمْشِيا، اِمْشينَ).

Whom you are calling, and what ending it takes

Examples

Common mistakes

• أُكْتُبْ -> اُكْتُبْ - the connecting alif is bare. Writing أ makes it a هَمْزَةُ القَطْع, which would still be pronounced after another word (wa-uktub instead of wa-ktub).
• اِكْتُبْ -> اُكْتُبْ - the alif echoes the stem vowel, and يَكْتُبُ has a ḍamma. Save the kasra for stems with a kasra or a fatḥa: اِجْلِسْ، اِفْتَحْ.
• تَكْتُبْ رَقْمَكَ (as an order) -> اُكْتُبْ رَقْمَكَ - the تـ must actually come off. Left on, the form is only a jussive waiting for a لَمْ or a لا.
• اُكْتُبونَ -> اُكْتُبوا - the imperative is jussive, so نونُ الرَّفْعِ is deleted and the plural ends in ـوا with its silent alif. Only اُكْتُبْنَ keeps a ن, and that ن is the subject.
• لا تَكْتُبُ هٰذا هُنا. (meaning “don’t write”) -> لا تَكْتُبْ هٰذا هُنا. - with a ḍamma the sentence is a plain statement, “you do not write this here”. A prohibition needs the jussive sukūn.
• لا اُكْتُبْ -> لا تَكْتُبْ - the imperative has no negative form of its own. Forbidding always sends you back to the second-person مُضارِع مَجْزوم.
• اُقولْ -> قُلْ - a hollow verb shortens in the jussive, and the shortened stem starts with a vowel, so there is nothing for a helping alif to do.
• اِمْشي (to a man) -> اِمْشِ - the weak final letter drops in the jussive. The written ي belongs to the feminine singular only.
• يا مُحَمَّدٌ -> يا مُحَمَّدُ - a called name never carries tanwīn. One ḍamma and stop.
• يا صاحِبُ البَيْتِ -> يا صاحِبَ البَيْتِ - once the addressee owns a following noun it is an إِضافَة, and the first half goes مَنْصوب. Same reason for يا أَبا عُمَرَ, not *يا أَبو عُمَرَ.
• يا الأُسْتاذُ -> يا أَيُّها الأُسْتاذُ - يا cannot stand in front of الـ; أَيُّها (or أَيَّتُها) is the required buffer.

Tips

• Never build an imperative from scratch. Say the أَنْتَ jussive out loud, drop the تـ, and listen: if what is left cannot be pronounced, add the alif. Three seconds, no new paradigm.
• The alif’s vowel is an echo, not a rule to look up. Chant اُدْخُلْ، اُنْظُرْ، اُكْتُبْ against اِجْلِسْ، اِفْتَحْ، اِذْهَبْ and your ear will start choosing correctly.
• Learn the short irregulars as vocabulary items, not as derivations: قُلْ، كُنْ، خُذْ، كُلْ، بِعْ، قِفْ، نَمْ. Seven one-syllable words cover most of the commands you will ever give.
• Do not avoid the imperative out of politeness - Arabic uses it freely and softens it with a phrase, not with grammar: مِنْ فَضْلِكَ، لَوْ سَمَحْتَ، رَجاءً، تَفَضَّلْ.
• Drill positive and negative side by side (اُكْتُبْ / لا تَكْتُبْ, خُذْ / لا تَأْخُذْ). They look unrelated but come from the same مَجْزوم, and pairing them stops you inventing *لا اُكْتُبْ.
• When reading, stop hunting for the لا النّاهِيَة / لا النّافِيَة vowel. Real Arabic is unvocalized and the distinction is invisible; a sign, a recipe or an instruction manual is giving orders, an article is describing.
• With يا, ask one question: is the name standing alone or does it own something? Alone gives a ḍamma with no tanwīn; owning something (or carrying ـي) gives a fatḥa.
• Park لِيَكْتُبْ and لِنَذْهَبْ for now. Recognising them in a text is enough at A2; the five second-person forms are what you actually need to speak.