Rule 1: 1. Three sources of the quadriliteral verb
Most quadriliterals arise in one of three ways. (a) Reduplication. A two-letter root that names a sound or a movement is doubled to express repetition: زَلْزَلَ to shake, to quake, وَسْوَسَ to whisper, دَحْرَجَ to roll (د-ح-ر-ج, where the second half echoes the first in sound rather than letter), غَرْغَرَ to gargle, زَحْزَحَ to shift, to budge. (b) Denominatives. A noun of four or more letters, often a borrowed one, is turned into a verb: كَهْرَبَ to electrify from كَهْرَبَاءُ electricity, تَلْمَذَ to take as a pupil from تِلْمِيذٌ, عَرْقَلَ to obstruct, زَخْرَفَ to ornament from زُخْرُفٌ ornament. (c) Formula verbs. The first letters of a familiar phrase are strung together: بَسْمَلَ to say بِسْمِ اللّٰهِ, حَمْدَلَ to say اَلْحَمْدُ لِلّٰهِ, حَوْقَلَ to say لَا حَوْلَ وَلَا قُوَّةَ إِلَّا بِاللّٰهِ. Verbs like تَرْجَمَ and سَيْطَرَ belong to none of the three groups: they are simply old four-radical roots.
زَلْزَلَ الِانْفِجَارُ نَوَافِذَ الْبُيُوتِ الْقَرِيبَةِ.
zalzala l-infijāru nawāfidha l-buyūti l-qarībati
The explosion shook the windows of the nearby houses.
Reduplicated root ز-ل.
دَحْرَجَ الْعُمَّالُ الْبَرَامِيلَ مِنَ الشَّاحِنَةِ.
daḥraja l-ʿummālu l-barāmīla mina sh-shāḥinati
The workers rolled the barrels off the lorry.
كَهْرَبَتِ الْبَلَدِيَّةُ شَوَارِعَ الْحَيِّ الْجَدِيدِ.
kahrabati l-baladiyyatu shawāriʿa l-ḥayyi l-jadīdi
The municipality electrified the streets of the new quarter.
Denominative from كَهْرَبَاءُ.
تَرْجَمَ الْمُوَظَّفُ الْإِعْلَانَ إِلَى الْعَرَبِيَّةِ.
tarjama l-muwaẓẓafu l-iʿlāna ila l-ʿarabiyyati
The clerk translated the notice into Arabic.
بَسْمَلَ السَّائِقُ قَبْلَ أَنْ يَعْبُرَ الْجِسْرَ.
basmala s-sāʾiqu qabla an yaʿbura l-jisra
The driver said bismillāh before crossing the bridge.
Formula verb from بِسْمِ اللّٰهِ.
حَمْدَلَ الرُّكَّابُ عِنْدَمَا وَصَلَ الْقِطَارُ سَالِمًا.
ḥamdala r-rukkābu ʿindamā waṣala l-qiṭāru sāliman
The passengers said al-ḥamdu li-llāh when the train arrived safely.