Short article on Duplicated or Doubled Verbs in Arabic, known as mudha’af.

Doubled Verbs Arabic

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What are Duplicated or Doubled Verbs in Arabic?

Certain words in the Arabic language are such that their second and third radicals are the same letter. Such words are deemed to be irregular and they have certain rules that govern their conjugation. This type of irregularity is termed مضاعفة (Duplication) and the rules associated to it are termed The Rules of إدغام (Gemination).

This tutorial covers the rules of gemination, especially as they relate to verbs. One should not be confused by the title Duplicated Verbs; it is not the verb that is duplicated but the letters within it.

For a more detailed picture of where this tutorial fits into Arabic morphology, consult the introduction to this section entitled Arabic Morphology, and specifically the section on morphophonemic rules and weak verbs.

Types of Duplication

Theoretically speaking, a word in the language should be termed مضاعف (duplicated) when one of the following is true

1.       the first and second radicals are the same (e.g.ٌ دَدَن)

2.       the first and third radicals are the same

3.       the second and third radicals are the same

4.       all three radicals are the same

However, options (1), (2), and (4) are either never realized in the language or are extraordinarily rare and do not undergo change. Thus we need only concern ourselves with option (3). There is a small caveat of interest, however. There is a small debate among morphologists regarding 4-lettered verbs in which the first and third letters are the same as well as the second and fourth. An example of such verbs is given below.


There are three opinions with respect to such verbs.

1.       All four of the letters are original and base, so there is no duplication

2.       Such verbs are actually 3-lettered and their form has been achieved by copying the first radical between the second and third radicals (the original was هلّ)

3.       Such verbs are actually 3-lettered and their form has been derived from the تفعيل paradigm (the original was هلّل). This means that هلهل is a second-level derivation since هلّل is itself derived from هلّ

In any event, these verbs do not experience morphophonemic change and they will not be discussed further.

The Scope of Gemination Rules

The application of the gemination rules is not as wide as that of other rules. For example, the rules of Hamza verbs (الأفعال المهموزة) which are known collectively as تخفيف, as well as the rules of assimilated, hollow, and deficient verbs (الأفعال المعتلة) which are collectively known as إعلال or تعليل apply to verbs, gerunds, derived nouns, and many other types of words in the language. Gemination, however, applies to verbs and derived nouns, but many gerunds and other types of nouns are not included. Consider the following as an example.


Here the second and third radicals are the same, thus we would expect them to geminate. But this does not happen. The reason is because all the rules associated to irregular verbs – whether they be تخفيف, تعليل, or إدغام – are designed to ease pronunciation, yet the pronunciation of the above word is already quite easy. For this reason gemination has a slightly limited scope.

As a result of this, the rules that are given in the remainder of this tutorial should not be thought of as universally applicable (they have many exceptions). There will be categories of words for which the upcoming rules do not apply. There is no sense in listing these categories of nouns at this point; one will discover them through exposure, and that is best.

Gemination Rules

There are two major rules for gemination. The first is as follows

Rule 1



if two identical, vowelled radicals occur side-by-side in the same lexical word and the letter before them is vowelled, the two will geminate and the resulting letter will be given the vowel of the second duplicate

One of the applications of this rule is in the perfect tense verbs (active and passive). Three examples have been given below. The original forms were as follows

فَرَرَ، ظَلِلَ، لَبُبَ

Notice that, in each case, the final two radicals of the verb are identical, they are both vowelled, and the letter before them is also vowelled. As a result of this, the two identical letters geminate and the vowel given to the resulting letter is the vowel on the third radical (the second duplicate). Since the vowel on the third radical is the same for each of the three cases above, the three examples end up looking the same:

فَرَّ، ظَلَّ، لَبَّ

This gemination, however, only occurs for the first five conjugations. This is because, beyond that, it is no longer the case that the two identical letters are both vowelled. Below is a chart with a few tangible examples that clarifies this.
































1.       Duplicated verbs are not realized in paradigms فتَح-يفتَح and حسِب-يحسِب. But consider other (more advanced) popular paradigms. In how many of those do you expect Rule 1 to take effect?

2.       Consider the derived nouns for simple 3-lettered verb paradigms. In how many of those do you expect Rule 1 to take effect? Remember to consider different forms of each derived noun, as well as the plurals.

3.       Can you give examples of gerunds where Rule 1 applies and takes effect, and examples where it applies but does not take effect?

The second of the two major rules of gemination is the following. Notice the similarity between the two rules.

Rule 2



if two identical, vowelled radicals occur side-by-side in the same lexical word and the letter before is non-vowelled, the vowel from the first of the duplicates will transfer to the letter before, then the duplicates will geminate

Rule 2 applies to the imperfect verb (both active and passive) as well as the imperatives. Consider the following original forms.

يَفْرِر، يَظْلَل، يَلْبُب

Here is an instance where there are duplicate letters, both of which are vowelled, and before them is a non-vowelled letter. In such situations, the vowel from the first duplicate will transfer to the previous letter. This results in the following.

يَفِرْر، يَظَلْل، يَلُبْب

Gemination is then applied, giving us the following conjugations.

يَفِرّ، يَظَلّ، يَلُبّ


This rule applies to all conjugations of the imperfect verb except 6 and 12 (the plural feminine verbs), where the conditions for Rule 2 are not met.


1.       Consider the perfect tense for the advanced paradigms. Which one of the two rules will apply in each case?

2.       Consider the imperfect tense for the advanced verb paradigms. Which of the two rules will apply in each case?

3.       Consider the imperative verbs for paradigms إفعال, تفعيل, مفاعلة, تفعل, and تفاعل. Which of the two rules, if any, will apply in these cases?

4.       Form the active and passive participles for the advanced verb paradigms. You can use verbs from the list of practice verbs.

There is one more point to discuss which relates to the jussive form of the imperfect verbs. Consider those conjugations (active and passive) which do not end in a ن (there are five of these).



Conj. #



لم يُفَر

لم يَفِر




لم تُفَر

لم تَفِر




لم تُفَر

لم تَفِر




لم أُفَر

لم أفِر




لم نُفَر

لم نَفِر


A problem occurs when we attempt to form the jussive conjugations, including the imperatives. The final letter of these conjugations must be made ساكن. This, however, poses a problem since a geminated letter cannot be stripped of its vowel; this would result in two successive ساكن.

In order to alleviate this problem for jussive verbs (not the imperatives), the following options are available.

1.       The final letter may be given a فتحة because that is the lightest vowel and the closest to ساكن

لم يَفِرَّ، لم يَظَلَّ، لم يَلُبَّ

2.       The final letter may be given a كسرة because this is the vowel typically used to alleviate problems related to the gathering of two ساكن

لم يَفِرِّ، لم يَظَلِّ، لم يَلُبِّ

3.       If the first radical has a ضمة, the final letter may be give the same vowel in order to match

لم يَلُبُّ

4.       The gemination may be undone

لم يَفْرِرْ، لم يَظْلَلْ، لم يَلْبُبْ

And in the case of the imperatives, if speech is begun with the verb, Rule 2 must be undone. Notice that the eliding Hamza will then be required.

اِفْرِرْ، اِظْلَلْ، اُلْبُبْ

Otherwise, if the verb occurs in the middle of speech, the following options are available.

1.       The tribe of نجد give the final letter a فتحة

فِرَّ، ظَلَّ، لُبَّ

2.       The tribe of بنو أسد give the final letter a فتحة if the next letter in the sentence is vowelled, and a كسرة otherwise

فِرَّ وَ…، ظَلَّ وَ…، لُبَّ وَ…

فِرِّ الْـ…، ظَلِّ الْـ…، لُبِّ الْـ…

3.       The tribe of بنو كعب give the final letter a كسرة

فِرِّ، ظَلِّ، لُبِّ

4.       Yet others match the vowel on the final letter with that of the first radical

فِرِّ، ظَلَّ، لُبُّ


1.       Conjugate the verb دب-يدُب using imperfect jussive once for each of the conjugation options

2.       Repeat question (1), only this time, do not recite a separate table for each option; recite a single table and repeat the conjugations for which different options are available

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More Complicated Rules for Enquiring Minds





if a duplicated verb is in paradigm سمِع-يسمَع or it is passive, and we’re working with the perfect conjugations in which Rule 1 does not apply, it is permissible to drop the first of the two duplicated radicals; it is also possible to transfer its vowel to the first base letter before dropping

فَظَلْتُمْ تَفَكَّهُوْنَ



in certain rare situations, it is permissible, instead of maintaining the duplicated letters in the perfect verb, to convert the second to a ياء

فَأَمْلَيْتُ لِلَّذِيْنَ كَفَرُوْا


in conjugations 6 and 12 of the imperfect verb, it is permissible to drop the first of the two duplicate letters after transferring its vowel to the previous letter

يَفْرِرْنَ becomes يَفِرْنَ


if a verb is both مضاعف and, moreover, the duplicated letter is a weak letter, Rule 1 may be used or it may be forgone; in practice, this only applies to two verbs: حيّ and عيّ

حَيَّ and حَيِيَ


it is obvious that when two duplicate letters occur side-by-side in the same lexical word where the first is non-vowelled and the second is vowelled, the two will geminate unconditionally


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