Verbs With a Weak Middle Letter

Hollow verbs are a major category of triliteral roots where the second radical is a weak letter.

1. The Hidden Root:
The Alif you see in the past tense (like in زار 'he visited' or باع 'he sold') is never a root letter. It is a transformation of either a و (wāw) or a ي (yā’). You can usually find the true root by looking at the present tense (يزور vs. يبيع).
Note: For verbs like خاف (to fear), the present tense يخاف still contains an Alif; in these cases, the verbal noun (خوف) or a dictionary root entry can identify the underlying و.

2. Past Tense Deletion:
When a suffix requires sukūn on the final root consonant, as with -tu, -ta, -nā, and feminine plural -na, the middle long vowel shortens. The feminine singular -at is different: قالتْ retains the long vowel.

• If the root is و, the first letter takes a ḍamma (e.g., قلتُ from قال/قول).
• If the root is ي, the first letter takes a kasra (e.g., بعتُ from باع/بيع).
• Exception: Verbs following the fa‘ila pattern, like خاف (root خ-و-ف), take a kasra (خفتُ) regardless of the root letter.

3. Passive Voice Transformation:
In the passive in the past, the common unsuffixed Form I pattern changes the middle weak letter into a long ي (yā’) and the first letter takes a kasra, regardless of the original root. For example, قال (he said) becomes قيل (it was said) and باع (he sold) becomes بيع (it was sold). In the passive in the present, the middle letter becomes an Alif, such as يقال (it is said).

4. Jussive, Imperative, and Feminine Plural:
When the final stem consonant has sukūn in the jussive or imperative, and in the feminine plural of the present tense (using the suffix -na), the long vowel is dropped to prevent the meeting of two consonants (sukūns). For example, the command for 'Say!' is قلْ (masculine) but becomes قولي (feminine) because the vowel suffix protects the long vowel. Similarly, 'they (f.) say' becomes يقلْنَ.

Form I Participles: For a contracted hollow Form I verb, the active participle normally has hamza in the middle: قَالَ → قَائِل, بَاعَ → بَائِع. The passive participles include مَقُول (said) and مَبِيع (sold), with the weak stem adjusted rather than mechanically retaining every letter of مفعول. Learn these with the verb.

Scope of the Rule: The paradigms above describe contracted Form I verbs such as قال and باع. A weak middle root consonant need not disappear in other forms: Form II صَوَّرَ and Form III حَاوَلَ retain consonantal و. Other derived forms, such as أقام and استقام, have their own contraction patterns. Even some Form I verbs retain their consonant, so confirm the actual verb’s paradigm.