A single root remains recognizable through four grammatical combinations, while vowels and particles change its grammatical meaning.
Word / formMeaning / explanation
كَتَبَhe wrote; affirmative active.
كُتِبَit was written; affirmative passive.
مَا كَتَبَhe did not write; negative active.
مَا كُتِبَit was not written; negative passive.
All contain the root letters ك، ت، ب. Passive voice requires a different verbal vowel pattern; past negation adds mā before the verb. These are separate operations.