This tutorial deals with irregular verbs (as well as gerunds and derived nouns) whose second radical is a واو or a ياء. Such verbs are termed الأفعال الجوفاء (sing. الفعل الأجوف) and there are some morphophonemic rules that need to be considered when conjugating them. These rules are termed تعليل or إعلال and the rest of this tutorial is dedicated to their analysis.

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

Introduction

Since the categorization of verbs based on their level of weakness is parallel to their categorization based on verbal paradigms, hollow verbs can naturally be witnessed to occur in basically all major paradigms. However, in this tutorial we will focus on only the basic ones, using the examples given below. Analyzing the conjugation of these specific verbs will sieve out all major regulations associated to hollow verbs, and these canonical examples will be a sufficient analysis.

Specific Base Letters Used as an Example		Paradigm
ق، و، ل		فعَل / يفعُل
ب، ي، ع		فعَل / يفعِل
خ، و، ف		فعِل / يفعَل

Hollow verbs can only occur in these three paradigms of the six basic paradigms. Their occurrence in any of the other three is possible but quite rare. Hollow verbs can occur in all of the advanced paradigms, but not all of those paradigms require morphophonemic changes. At the end of this tutorial, we will briefly discuss hollow verbs in paradigms other than the three mentioned above.

The Perfect Tense

Active

Rule 1
	if a vowelled واو or ياء is preceded by a فتحة in the same lexical word, it will change to an الف
Memory Aid
	vowelled واو or ياء preceded by فتحة becomes الف

If we attempt to use the examples given above and place them on their respective templates in order to form past tense verbs, the following will result.

خَوِفَ

بَيَعَ

قَوَلَ

Notice that in each of the three cases there is a weak letter (واو or ياء) which is vowelled and that before it is a فتحة. Based on Rule 1, the weak letter must become an الف, and the following conjugations result.

خافَ

باعَ

قالَ

The conjugations yielded by Rule 1 look exactly the same irrespective of their paradigm. That is until we reach conjugation 6 onwards of the past tense table. In these 9 conjugations, the third radical of the verb loses its vowel, resulting in a vowel-consonant cluster.

خافْنَ

باعْنَ

قالْنَ

Applying the rules of cluster reduction, we get the following.

خَفْنَ

بَعْنَ

قَلْنَ

This, however, is not how it’s done. The long vowel, الف, is dropped based on the rules of cluster reduction, but the فتحة on the letter before the الف is not necessarily maintained. In the case of قال (verbs from the فعَل / يفعُل paradigm), the فتحة is changed to a ضمة in order to indicate that the long vowel that dropped was a واو. Similarly, the فتحة in the case of باع (verbs from the فعَل / يفعِل paradigm) is changed to a كسرة to show that the letter that dropped was a ياء.

Now, using a ضمة to indicate that a واو has dropped in paradigm فعَل / يفعُل is fine because only those hollow verbs whose middle radical is a واو may be realized in this paradigm. Similarly, using a كسرة to indicate that a ياء has dropped in paradigm فعَل / يفعِل is fine because only those hollow verbs whose middle radical is a ياء may be realized in this paradigm. But as for paradigm فعِل / يفعَل, it sees both types of hollow verbs – those with واو as well as those with ياء. The logical thing to do in this case would be to leave the فتحة in these 9 conjugations as is in order to differentiate it from the other two paradigms. However, what is actually done is that the فتحة is changed to a كسرة, and the following conjugations result.

خِفْنَ

بِعْنَ

قُلْنَ

Exercise: Conjugate these three verbs in the past tense.

Passive

Rule 2
	in the passive prefect conjugations, the كسرة from the middle radical will transfer to the first radical

If we attempt to construct the past passive verbs using our examples, the following conjugations will result.

خُوِفَ

بُيِعَ

قُوِلَ

Rule 2 sees that these are passive perfect conjugations and it therefore dictates that the كسرة from the middle letters should be transferred to the right. Hence the conjugations end up as follows.

خِوْفَ

بِيْعَ

قِوْلَ

However, there is another very important and very widely applicable rule that comes into play at this point and further changes the above conjugations.

Rule 3
a)	if a non-vowelled ياء is preceded by a ضمة, the ضمة will become a كسرة (occasionally, however, the ياء will become a واو instead)
(the ميزان rule) b)	if a non-vowelled واو is preceded by a كسرة, the واو will become a ياء

This rule is designed to take the two diphthongs that are not allowed in the phonology of the Arabic language – namely ـِوْ and ـُيْ – and transform them into one of the two that are allowed – namely ـَوْ and ـَيْ.

Notice that Rule 3b applies to the case of قال and خاف, and not the case of باع. Applying the rule yields the following conjugations.

خِيْفَ

بِيْعَ

قِيْلَ

Notice again that all three paradigms look the same, just as they do with regular verbs. That is until we reach conjugation 6 and onwards. These 9 conjugations again experience the same changes that were applied to them in the active tables. Recall what occurred in the active tables; the following conjugations will result.

خِفْنَ

بِعْنَ

قُلْنَ

This is interesting because both the active and passive tables now look exactly the same from conjugation 6 onwards.

Exercise: Conjugate the three examples in the perfect passive. Juxtapose the active and passive tables to compare where conjugations are similar and where they are not.

The Imperfect Tense

Rule 4
	If a vowelled واو or ياء is preceded by a non-vowelled letter in the same lexical word, its vowel will transfer to that preceding letter. In the case where the transferred vowel is a فتحة, the واو or ياء will become an الف in addition.

Conjugating the three examples in the imperfect tense, we would expect the verbs to look as follows based on regular verb conjugation.

يَخْوَفُ

يَبْيِعُ

يَفْوُلُ

But in each of the three above cases, a vowelled weak letter is preceded by a non-vowelled letter. Rule 4 then comes into play and dictates that the vowel from the weak letter should shift right. We then see the following results.

يَخَوْفُ

يَبِيْعُ

يَفُوْلُ

But Rule 4 also dictates that, in the case where the transferred vowel is a فتحة, the weak letter should become an الف. This is the case with يخوف, ergo the final results below