This article proposes a historical explanation for the development of Niphal verbal forms in Biblical Hebrew. Niphal forms are roughly classified into two patterns, niqtal (with suffixes) and yiqqɔtel (with prefixes or circumfixes). Some scholars also distinguish hiqqɔtel (imperative) from yiqqɔtel based on their supposed origins. The following three points are discussed in this article.
(1) By internal reconstruction, it appears that the niqtal pattern originated from **naqtal. As Origens Hexaplaic Greek transcription shows a *nɛqtɛl pattern, it is possible to assume the shift **naqtal＞*nɛqtɛl around third century C. E. After that, the change *nɛqtɛl＞niqtal occurred through vividation of the verbal stem.
(2) Both yiqqɔtel and hiqqɔtel have the initial vowel i, which was added to avoid the initial consonantal cluster. The epenthetic vowel i in the initial position of the word is attested not only in Hebrew, but also in many other Semitic languages. The underlying forms may have been **yqqatil and **qqatil, to each of which the epenthetic vowel i was added for ease of pronunciation, a change which resulted in *yiqqatil (＞yiqqɔtel) and *iqqatil respectively. The initial h- was then added to the latter to contain the epenthetic vowel within a syllable, a change which resulted in the hiqqɔtel.
(3) According to G. Buccellati’s analysis in Akkadian verbal forms, only the initial and final vowels of the verbal stem are morphologically meaningful and the other middle stem vowels (realized as a) were inserted to build the shape of the verb. It is possible to suppose that the a stem vowels in **naqtal and **y(i)qqatil in Proto-Hebrew are the vestiges of the same inserted meaning-neutral intervening vowels, though they acquired the new function of creating the passive form by alternation of the stem vowels at the Proto-Central Semitic stage.