In short

Lesson 47 built its forms by working inside the word: doubling a radical, stretching a vowel, gluing a تَ on the front. The remaining forms do something visibly different - they start the past tense with an extra alif: اِنْكَسَرَ، اِجْتَمَعَ، اِحْمَرَّ، اِسْتَقْبَلَ. The reason is mechanical. The patterns themselves begin with a vowelless consonant (نْكَسَرَ، سْتَقْبَلَ) and no Arabic word may begin that way, so the language props the word up with an alif and a kasra. That prop is هَمْزَةُ الوَصْلِ, and understanding it is most of this lesson.

These are not exotic forms. اِسْتَخْدَمَ، اِسْتَعْمَلَ، اِجْتَمَعَ، اِخْتَلَفَ، اِتَّصَلَ، اِنْتَظَرَ، اِنْقَطَعَ are among the most frequent verbs in any newspaper, and the four-radical verbs تَرْجَمَ and بَرْمَجَ are how modern Arabic coins new ones. Learn the six patterns in this lesson and, together with lesson 47, you can conjugate essentially any sound MSA verb you meet.

The rule

1. What is added, and where. Each form adds fixed material to the three radicals ف ع ل. Form VII prefixes نْ; Form VIII inserts a تَ after the first radical; Form IX doubles the last radical and adds nothing else; Form X prefixes سْتَ. Because all four then begin with a consonant carrying a sukūn, the past tense - unlike the imperfect - needs the supporting alif in front.

• VII: نْ in front of the root → اِنْفَعَلَ.
• VIII: تَ inserted after the first radical → اِفْتَعَلَ.
• IX: the last radical doubled, nothing else → اِفْعَلَّ.
• X: سْتَ in front of the root → اِسْتَفْعَلَ.

2. The central point: that alif is هَمْزَةُ الوَصْلِ, never هَمْزَةُ القَطْعِ. You met the distinction in the pronunciation guide’s hamza lesson. A قَطْع hamza is a real consonant and is written with a seat - أَكَلَ، إِسْلامٌ. A وَصْل hamza is a disposable launching device: it exists only so the word can be started, and in these forms it is written as a bare alif with a kasra under it. So the correct spellings are اِنْكَسَرَ، اِجْتَمَعَ، اِسْتَقْبَلَ. Writing إِنْكَسَرَ or إِسْتَقْبَلَ with إ is one of the most visible spelling errors in learner Arabic, and unlike most of the vowelling in this path it stays visible when the vowel marks are stripped: استقبل is right, إستقبل is wrong on any page.

The same applies to everything else built on these patterns, including the verbal nouns you will meet in lesson 54: اِسْتِقْبالٌ، اِجْتِماعٌ، اِنْكِسارٌ, never إِسْتِقْبال.

3. It is pronounced only at the very start of an utterance. Put any word in front and the alif falls silent - the preceding word runs straight into the following consonant. In وَصَلَ المُهَنْدِسونَ وَاجْتَمَعوا فِي المَكْتَبِ the alif of اِجْتَمَعوا is written but not heard; the وَ attaches directly to the ج. This is exactly what الـ does in الكِتاب, and for the same reason.

If the preceding word ends in a sukūn, it cannot run into anything, so it takes a helping vowel, usually a kasra: هَلْ + اِسْتَخْدَمْتَ gives هَلِ اسْتَخْدَمْتَ. Notice how the fully vocalized spelling records this: the kasra moves onto the هَلْ and the alif is left bare.

4. There is no alif at all in the مُضارِع. The imperfect prefixes يَ تَ أَ نَ already supply an opening consonant and vowel, so the prop is not needed and is simply not there: يَنْكَسِرُ، يَجْتَمِعُ، يَسْتَقْبِلُ. The form يَاسْتَقْبِلُ does not exist, and neither does يِسْتَقْبِلُ. For Forms VII, VIII and X the prefix vowel is a fatḥa, as it is in Form I and in Forms V-VI, and the stem vowel is a kasra; only the quadriliteral behaves differently (point 11).

The imperative, which you built in lesson 36, keeps the waṣl alif because it too begins with a sukūn: اِسْتَقْبِلْ، اِجْتَمِعوا، اِنْتَظِرْ.

5. Form VII اِنْفَعَلَ: it happened by itself. Form VII takes a transitive Form I verb and makes it intransitive, with the sense that the action simply occurred and no agent is mentioned: كَسَرَ “he broke (something)” → اِنْكَسَرَ “it broke”; قَطَعَ → اِنْقَطَعَ “it was cut off”; فَتَحَ → اِنْفَتَحَ “it opened”; شَغَلَ → اِنْشَغَلَ “he became busy”. Because of that meaning, a Form VII verb never takes a direct object. If you want “the boy broke the window”, the verb is Form I: كَسَرَ الوَلَدُ النّافِذَةَ.

Form VII is far less productive than VIII and X: roots beginning with ن، ر، ل، م، و، ي practically never use it, and where the verb is missing Arabic reaches for Form VIII instead.

6. Form VIII اِفْتَعَلَ: the ت that moves in after the first radical. It is one of the busiest forms in the language, alongside II and IV. Its classical value is reflexive or middle - جَمَعَ “he gathered (things)” → اِجْتَمَعَ “they gathered, met” - but in practice most Form VIII verbs are just independent vocabulary: اِنْتَظَرَ “wait”, اِخْتَلَفَ “differ”, اِعْتَمَدَ “rely”, اِشْتَغَلَ “work”. Learn the meaning from the dictionary; use the pattern to conjugate.

7. Form VIII’s ت changes shape after certain first radicals. The infixed ت sits immediately after the first radical, and Arabic will not tolerate some of the resulting pairs. Three adjustments cover everything you will meet:

• After the emphatics ص ض ط ظ the ت hardens into ط: ص ب ر → اِصْطَبَرَ، ض ر ب → اِضْطَرَبَ. Where the radical is itself ط or ظ, the two merge into one doubled letter: ط ل ع → اِطَّلَعَ.
• After the voiced dentals ز د ذ the ت voices into د: ز ح م → اِزْدَحَمَ. Again, a د or ذ radical merges: ذ خ ر → اِدَّخَرَ.
• A first radical و disappears into the ت and doubles it: و ص ل → اِتَّصَلَ، و ف ق → اِتَّفَقَ. This is the assimilated verb (المِثال) of lesson 49; the same swallowing happens when the radical is ت: ت ب ع → اِتَّبَعَ.

None of this is optional and none of it is spelling licence. اِزْتَحَمَ and اِضْتَرَبَ are simply not Arabic words.

8. Form IX اِفْعَلَّ, in two lines. A closed little pattern for colours and physical defects, with the third radical doubled from the start: اِحْمَرَّ / يَحْمَرُّ “turn red”, اِصْفَرَّ / يَصْفَرُّ “turn yellow, go pale”, اِعْوَجَّ / يَعْوَجُّ “become crooked”. Because the doubling is built into the pattern, every Form IX verb is a مُضَعَّف verb and behaves like one: the two letters separate again before a consonant ending (اِحْمَرَرْتُ), which is lesson 49’s subject. Note the stem vowel: the imperfect is يَفْعَلُّ with a fatḥa, not the kasra of VII, VIII and X.

9. Form X اِسْتَفْعَلَ: asking, seeking, deeming. The سْتَ prefix classically means “ask for” or “seek” the meaning of Form I - عَلِمَ “know” → اِسْتَعْلَمَ “inquire” - or “consider something to be”: حَسُنَ “be good” → اِسْتَحْسَنَ “find good, approve of”. Many Form X verbs have drifted away from that into plain vocabulary, and these are the frequent ones: اِسْتَقْبَلَ “receive, welcome”, اِسْتَخْدَمَ “use, employ”, اِسْتَعْمَلَ “use”, اِسْتَخْرَجَ “extract”, اِسْتَمَرَّ “continue”.

10. The trap: count the radicals before you call something Form X. اِسْتَمَعَ / يَسْتَمِعُ “listen” looks like a Form X verb and is not. Its root is س م ع, and the س you see is the first radical, not the س of سْتَ; the verb is Form VIII, with the ordinary ت infix. Counting settles it instantly: after the alif, a Form X verb has five consonants (س، ت، then three radicals), a Form VIII verb has four.

اِسْتَقْبَلَ → س ت ق ب ل = five = Form X of ق ب ل. اِسْتَمَعَ → س ت م ع = four = Form VIII of س م ع.

The same root can even give you both, with different meanings: اِسْتَلَمَ “take delivery of” is Form VIII of س ل م, while اِسْتَسْلَمَ “surrender” is Form X of the same root - and there you can literally see the extra س.

11. The quadriliteral verb: four radicals, no alif. A small but useful class of verbs has four root letters instead of three. The base pattern is فَعْلَلَ: تَرْجَمَ “translate” (ت ر ج م), بَرْمَجَ “program” (ب ر م ج), فَلْسَفَ “philosophize” (ف ل س ف), زَلْزَلَ “shake”. It begins with a vowelled consonant, so no waṣl alif is involved at all.

Its imperfect is where learners slip: يُتَرْجِمُ, with a ḍamma on the prefix, exactly like Form II يُعَلِّمُ. Pair the two in your memory and you will never write يَتَرْجِمُ. The derived quadriliteral تَفَعْلَلَ adds a تَ in front - تَدَحْرَجَ “roll along” (د ح ر ج) - and it behaves like Form V instead: fatḥa prefix, fatḥa stem vowel, يَتَدَحْرَجُ. The rule of thumb from lesson 47 holds here too: a تَ at the front of the past means a fatḥa prefix in the present.

12. What this lesson leaves to others. The verbal nouns of these forms - اِنْكِسارٌ، اِجْتِماعٌ، اِسْتِقْبالٌ، تَرْجَمَةٌ - are lesson 54; their participles (مُجْتَمِعٌ، مُسْتَخْدَمٌ) are lesson 53; their passives are lesson 52. Roots with a weak middle radical, which reshape these patterns badly (اِخْتارَ، اِسْتَقالَ), wait for lesson 50, and doubled and assimilated roots for lesson 49. Apart from the Form VIII و of point 7 and the doubling built into Form IX, everything below uses sound roots.

Forms & patterns

The six patterns at a glance, third person masculine singular:

Form VII, ك س ر:

Form VIII, ج م ع:

Form X, two verbs side by side - ق ب ل and خ د م:

Form IX, ح م ر. Watch the doubled ر come apart before ـتُ and ـنا:

The two quadriliterals - ت ر ج م and د ح ر ج. Compare the prefix vowels in the two imperfect columns; that ḍamma is the whole difference:

Form VIII’s assimilated ت:

The tables show five of the thirteen person slots. The dual, the feminine plural and the second person are built with the endings you already know from lessons 14 and 18 - the stem never changes. The verbal noun, the participles and the passive are left to lessons 54, 53 and 52.

Examples

Common mistakes

• إِسْتَقْبَلَ الرَّئيسُ الضُّيوفَ -> اِسْتَقْبَلَ الرَّئيسُ الضُّيوفَ - the alif of Form X is هَمْزَةُ وَصْلٍ and is written bare, never with a seat. The same goes for the verbal noun: اِسْتِقْبالٌ, not إِسْتِقْبال.
• إِنْكَسَرَ الزُّجاجُ -> اِنْكَسَرَ الزُّجاجُ - identical rule for Form VII, and for VIII and IX. If a form begins with an added alif, that alif is وَصْل by definition.
• يَاسْتَخْدِمُ المُهَنْدِسُ الحاسوبَ -> يَسْتَخْدِمُ المُهَنْدِسُ الحاسوبَ - the waṣl alif belongs to the past tense only. The imperfect prefix already gives the word a vowel to start on, so nothing is propped up and nothing is written.
• اِزْتَحَمَ السّوقُ -> اِزْدَحَمَ السّوقُ - Form VIII’s ت becomes د after a ز. The written form follows the pronunciation; there is no “underlying” spelling to preserve.
• اِضْتَرَبَ الوَضْعُ -> اِضْطَرَبَ الوَضْعُ - after an emphatic radical the ت becomes ط. Learn اِضْطَرَبَ، اِصْطَبَرَ، اِطَّلَعَ as whole words and the rule takes care of itself.
• اِوْتَصَلَ بي أَمْسِ -> اِتَّصَلَ بي أَمْسِ - a first radical و is swallowed by the ت and leaves a shadda behind. The root is still و ص ل, which is where the dictionary puts the verb.
• اِسْتَلَمَ الجَيْشُ لِلْعَدُوِّ -> اِسْتَسْلَمَ الجَيْشُ لِلْعَدُوِّ - اِسْتَلَمَ is Form VIII of س ل م (“take delivery of”); “surrender” is the Form X of the same root, with the extra س of سْتَ in front of all three radicals. Count the consonants: four means VIII, five means X.
• يَتَرْجِمُ الطّالِبُ الرِّسالَةَ -> يُتَرْجِمُ الطّالِبُ الرِّسالَةَ - the plain quadriliteral takes a ḍamma on the imperfect prefix, like Form II يُعَلِّمُ. Its تَ-form relative is the one with the fatḥa: يَتَدَحْرَجُ.
• اِحْمَرَ وَجْهُها -> اِحْمَرَّ وَجْهُها - Form IX is doubled by definition. Drop the shadda and the word is not a weaker Form IX, it is nothing at all.
• اِنْكَسَرَ الوَلَدُ النّافِذَةَ -> كَسَرَ الوَلَدُ النّافِذَةَ - Form VII says that something broke, not that somebody broke it, so it can never carry a direct object. Name the agent and you need Form I.

Tips

• Fix one sentence per pattern in memory with the alif at the very front, where it is actually pronounced: اِجْتَمَعَ المُدَراءُ، اِسْتَقْبَلْنا الضُّيوفَ. Then every other occurrence is just that word with the alif gone quiet.
• Always store a new verb as a pair, past and present: اِسْتَخْدَمَ / يَسْتَخْدِمُ. The second half of the pair is where the pattern is clearest, because the distracting alif is not there.
• Count consonants before you name a form. Five after the alif with سـ تـ in front is Form X; four with a ت in second place is Form VIII. اِسْتَمَعَ is the verb that catches everyone.
• Meaning hooks, rough but useful: VII “it happened by itself”, VIII “middle voice, or just a new word”, IX “it changed colour”, X “ask for it, or consider it so”.
• For the dictionary, strip the alif and the pattern letters and look up the radicals: ج م ع for اِجْتَمَعَ, و ص ل for اِتَّصَلَ. Lesson 22 is the drill for this, and Form VIII with an assimilated و is the case where it saves you the most time.
• Quadriliterals are how the language keeps growing: بَرْمَجَ from a borrowed noun, فَلْسَفَ from a borrowed one too. When you meet a new four-consonant verb, assume فَعْلَلَ / يُفَعْلِلُ and you will almost always be right.
• Ignore for now which verbs each root happens to have. Almost no root fills out all ten forms, and guessing a Form VII that does not exist is a more common failure than mis-conjugating one that does. Read, collect, and use what you have seen.