Choosing a Passive Subject

When dealing with verbs that naturally take two objects (like kupa 'to give') or verbs extended with the applicative extension to indicate a beneficiary, maleficiary, or recipient (like kupikia 'to cook for'), you must choose which object becomes the subject in a passive sentence.

In English, you can say either 'The student was given a book' or 'The book was given to the student'. In Swahili, only the first option is grammatically correct.

The Rule:
For benefactive or recipient applicatives, only the beneficiary/recipient (usually a person or animal) can be promoted to the subject of the passive verb. The verb will take the subject agreement marker for that animate noun. The inanimate object (the theme) stays right where it is, after the verb. (Note: Instrumental or locative applicatives can sometimes promote the inanimate theme, but benefactives strictly promote the beneficiary).

Morphology:
The passive extension -w- (or -iw-/-ew-) attaches to the verb stem. Crucially, it must attach after any applicative or causative extensions. For example, pika (cook) → pikia (cook for) → pikiwa (be cooked for). Additionally, the object marker that was present in the active sentence drops in the passive form because the beneficiary has been promoted to the subject.

Active: Mama alimpikia Juma chakula. (Mother cooked food for Juma.)
Passive: Juma alipikiwa chakula na mama. (Food was cooked for Juma by mother. Literally: Juma was cooked-for food by mother.)

Incorrect: *Chakula kilipikiwa Juma na mama. (This is strictly ungrammatical in Swahili, despite being a natural thought for English speakers.)

Alternative: If you want to make the inanimate theme the subject, you must use the basic passive verb and the phrase kwa ajili ya (for the sake of). For example: Chakula kilipikwa na mama kwa ajili ya Juma. (The food was cooked by mother for Juma).

Example with kupa:
Active: Mwalimu alimpa Juma kitabu. (The teacher gave Juma a book.)
Passive: Juma alipewa kitabu na mwalimu. (Juma was given a book by the teacher.)
Incorrect: *Kitabu kilipewa Juma na mwalimu.

Even if you change the word order in the active sentence for emphasis, the rule remains the same: only the beneficiary can become the passive subject.

Give Has a Learned Passive:
Kupa → kupewa means “to give → to be given.” Treat -pewa as the established passive stem of -pa; its e is not predicted by simply inserting w into pa. For example, nilipewa kitabu means “I was given a book.”