Deverbal Nouns and Event Nominals | Swahili Grammar

Swahili can present an action as an event, a person who performs it, or a result produced by it. The class 15 infinitive kuandika can mean “to write” or “writing”; mwandishi names a writer; and maandishi names written material. These forms share lexical history, but they are not interchangeable versions of one English -ing word.

The essential distinction is between a productive construction and a lexical noun. A speaker can use almost any suitable infinitive as a class 15 event noun, but agent and result nouns have conventional shapes and noun classes that must be learned with the word. The wider concord pattern is mapped on the class 15 infinitives page. Unless marked otherwise, the forms below are neutral in (informal) and (formal) Standard Swahili.

The class 15 infinitive as an event noun

An infinitive consists of class prefix ku- plus a verbal stem. It can occupy positions where English uses an infinitive, a gerund, or an abstract event noun. As a subject, the whole infinitive controls class 15 ku- on a following predicate.

Kusoma kwa utulivu kunamsaidia Neema kukumbuka maelezo.

Reading quietly helps Neema remember the details.

Kuendesha usiku kunahitaji umakini mkubwa.

Driving at night requires great concentration.

In kusoma ... kunamsaidia, the first ku- creates the event nominal and the second ku- is subject agreement on kunamsaidia. English hides that relationship because “reading” has no grammatical gender or noun class.

An infinitive can also be an object or complement. It retains its verbal ability to take an object and adverbial information inside the event phrase.

Ameacha kutumia simu anapoendesha gari.

He has stopped using his phone when driving.

Tunapenda kupika chakula cha jioni pamoja mwishoni mwa wiki.

We like cooking dinner together at the weekend.

The objects simu and chakula cha jioni belong to kutumia and kupika. This is why the class 15 form remains more verb-like than a lexical noun such as matumizi “use” or mapishi “cooking/cuisine.”

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Use a ku- event when you want to preserve the action's participants and circumstances. Choose a lexical event noun when you want to classify, count, describe, or discuss the event as an established concept.

Referring to a particular performance of an action

Bare ku- names an activity or event type. Possessive and associative material can anchor it to a performer or context: kuondoka kwake “his/her leaving,” kufika kwa wageni “the guests' arrival.” The possessive or -a linker agrees with class 15.

Kuwasili kwa daktari mapema kuliwatuliza wagonjwa waliokuwa wakisubiri.

The doctor's early arrival reassured the patients who were waiting.

Kujiuzulu kwake ghafla kuliwashangaza wafanyakazi wote.

Her sudden resignation surprised all the employees.

These are event nominals, not clauses with an English-style possessive subject inserted before a gerund. The event remains class 15, so past subject concord is ku-li- in kuliwatuliza and kuliwashangaza.

Agent nouns name conventional roles

Many human nouns derived from verbs belong to classes 1/2. Common patterns include m-/wa- with agentive endings such as -aji or -i: mchezaji/wachezaji “player(s),” msomaji/wasomaji “reader(s),” and mwandishi/waandishi “writer(s).” The relationship is often transparent, but the exact derivative is lexical.

Msomaji huyu makini ameona kosa, na wasomaji hawa wengine wameliona pia.

This attentive reader noticed the error, and these other readers noticed it too.

Mchezaji mpya amefunga bao, lakini wachezaji wawili wameumia.

The new player scored a goal, but two players have been injured.

The singular and plural are expressed throughout the chain: msomaji huyu ame- versus wasomaji hawa wame-. Do not treat -aji as an English suffix that can be added freely to every verb. For example, a cook is conventionally mpishi, not a form invented by attaching -aji to kupika.

Some agent nouns describe an occupation, while others describe a participant on one occasion. Mwandishi can be a professional author or the writer of a particular document; context supplies the narrower reading.

Event and result nouns in established classes

Swahili also has lexical nouns whose stems are historically related to verbs. The ending -o occurs in many event, manner, and result nouns, but it is not fully productive: kucheza → mchezo “game/play,” kujenga → jengo “building,” and kupanga → mpango “plan.” Other derivatives use different shapes, such as kuandika → maandishi “writing/written material” and kutumia → matumizi “use/expenditure.”

Mchezo huu wa kirafiki umevutia watazamaji, na michezo ile ya ligi imeahirishwa.

This friendly match attracted spectators, and those league matches were postponed.

Jengo jipya limefunguliwa leo, na majengo mawili ya zamani yatarekebishwa.

The new building opened today, and two old buildings will be renovated.

Nimeusoma mpango huu, lakini sijakubali mipango yote iliyopendekezwa.

I have read this plan, but I have not accepted all the proposed plans.

Although mchezo, jengo, and mpango all have a historical verbal connection and an o in the final stem, their classes and plurals differ: mchezo/michezo (3/4), jengo/majengo (5/6), and mpango/mipango (3/4). There is no rule “replace final -a with -o and use one plural.”

The lexical noun may also narrow the meaning. Kuandika is the act of writing; mwandiko/miandiko can refer to handwriting, script, or style of writing, while maandishi commonly means writing or written material. Choosing among them changes what is being conceptualized, not merely the grammar.

Mwandiko wake unasomeka vizuri, lakini maandishi kwenye bango yamefifia.

Her handwriting is easy to read, but the writing on the sign has faded.

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When learning a deverbal noun, record four things together: its full singular form, its plural or mass behavior, its noun class, and its conventional meaning. The source verb alone does not predict all four.

Choosing between an event phrase and a lexical noun

Use a class 15 event nominal to foreground the action itself: kujenga daraja jipya “building a new bridge.” Use ujenzi when discussing construction as a field or process, and jengo for a built structure. English can use “building” for all three, which makes direct translation unreliable.

Kujenga daraja hili kutachukua mwaka mmoja, lakini ujenzi utaanza mwezi ujao.

Building this bridge will take one year, but construction will begin next month.

The object daraja hili follows verbal kujenga. By contrast, abstract ujenzi is a class 14 noun and controls u- in utaanza. A finished structure would instead be jengo, with class 5 agreement.

Common Mistakes

Treating a demonstrative as a required article

❌ Ile kusafiri kunachosha wakati wa mvua.

Incorrect — ile is a class 9 demonstrative, not an article; generic class 15 kusafiri stands bare here.

✅ Kusafiri wakati wa mvua kunachosha.

Traveling during the rainy season is tiring.

Giving a class 15 subject human agreement

❌ Kuogelea kila asubuhi ananipa nguvu.

Incorrect — the event kuogelea is class 15 and requires ku-, not human a-.

✅ Kuogelea kila asubuhi kunanipa nguvu.

Swimming every morning gives me energy.

Inventing an agent noun mechanically

❌ Msafiriaji huyo amechelewa kufika kituoni.

Incorrect as the ordinary noun for traveler — the established derivative is msafiri.

✅ Msafiri huyo amechelewa kufika kituoni.

That traveler was late arriving at the station.

Giving every event noun the same plural

❌ Majengo haya yameidhinishwa; mamipango hii pia imeidhinishwa.

Incorrect — mpango has the established class 3/4 plural mipango, not mamipango.

✅ Majengo haya yameidhinishwa; mipango hii pia imeidhinishwa.

These buildings have been approved; these plans have also been approved.

❌ Mwandiko wa barabara hii umechelewa.

Incorrect for road construction — mwandiko means handwriting or writing style.

✅ Ujenzi wa barabara hii umechelewa.

The construction of this road has been delayed.

Key Takeaways

Class 15 ku- productively turns a verbal event into a subject, object, or complement while preserving verbal objects and adverbials.
Agent nouns and event/result nouns are lexical: their exact form, class, plural, and meaning must be learned.
The ending -o appears in established deverbal nouns but is not a universal nominalizing rule.
Agreement follows the chosen noun: ku- for a class 15 event, wa- for plural human agents, and the relevant class concord for lexical results.

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