kujua — to Know | Swahili Grammar

Kujua is the broad everyday verb “know”: know a fact, know a person or place, and know how to perform a skill. The stem is vowel-final jua, so negative and subjunctive endings produce jui and jue. The extremely frequent formula sijui ranges from a literal “I do not know” to a conversational marker of uncertainty.

All unlabelled forms below are neutral current Standard Swahili. Uses of kufahamu associated with careful exposition are labelled (formal) where appropriate.

Practical paradigm

Form	I	you (sg.)	he/she	we	you (pl.)	they
present	ninajua	unajua	anajua	tunajua	mnajua	wanajua
past	nilijua	ulijua	alijua	tulijua	mlijua	walijua
perfect	nimejua	umejua	amejua	tumejua	mmejua	wamejua
future	nitajua	utajua	atajua	tutajua	mtajua	watajua
present negative	sijui	hujui	hajui	hatujui	hamjui	hawajui
past negative	sikujua	hukujua	hakujua	hatukujua	hamkujua	hawakujua
subjunctive	nijue	ujue	ajue	tujue	mjue	wajue

Present ninajua normally describes an existing state of knowledge. Perfect nimejua often presents newly acquired knowledge or a realization—“I have found out/now know”—rather than simply replacing the present because English can say “have known.”

Sasa nimejua kwa nini mashine ilikuwa ikizimika kila jioni.

Now I have found out why the machine kept switching off every evening.

The singular imperative is jua and the plural is jueni. Commands to “know” are semantically restricted, but they occur naturally in instructions or emphatic warnings: Jua haki zako “Know your rights”; Jueni kwamba muda ni mfupi “Know that time is short.” They sound more deliberate than ordinary conversational advice.

Jueni haki zenu kabla ya kusaini mkataba wa ajira.

Know your rights before signing an employment contract.

This plural imperative belongs naturally in (formal) public guidance.

Sikujua kwamba mkutano umehamishwa mpaka kesho.

I did not know that the meeting had been moved to tomorrow.

Tutajua matokeo rasmi baada ya kura zote kuhesabiwa.

We will know the official results after all the votes are counted.

Compare the builds ni-na-ju-a, si-ju-i, and ni-ju-e. Vowel-final jua keeps -a in affirmative indicatives, changes it to -i in present negative, and to -e in the subjunctive. Past negative si-ku-ju-a instead keeps final -a.

💡

Memorize sijui as a whole high-frequency form, then recognize its logic: first-person negative si- + stem ju- + negative final -i.

Knowing a fact

A noun can name the known information:

Je, unajua anwani mpya ya ofisi yetu?

Do you know the new address of our office?

A full fact commonly follows kwamba “that,” especially when clarity matters:

Najua kwamba umekuwa na wiki ngumu, kwa hiyo pumzika leo.

I know that you have had a difficult week, so rest today.

In everyday conversation, kwamba is often omitted when the boundary is clear:

Najua umefika salama kwa sababu Amina amenitumia ujumbe.

I know you arrived safely because Amina sent me a message.

This is not two unrelated sentences. The second finite clause supplies the content of what is known. In more complex (formal) writing, retaining kwamba can prevent ambiguity.

Questions and uncertainty often use kama “whether” rather than kwamba:

Sijui kama duka bado limefunguliwa saa hii.

I don't know whether the shop is still open at this hour.

Knowing a person or place

With a definite human object, Swahili normally marks that person inside the verb:

Unamjua fundi anayerekebisha simu kwenye soko kuu?

Do you know the technician who repairs phones at the main market?

The build is u-na-m-ju-a: subject + present + class 1 human object + stem. English simply places “the technician” after know, but Swahili indexes the definite animate object with -m-.

Places and institutions can also be familiar objects:

Ninaijua njia ya kwenda stendi, lakini siijui njia ya kurudi.

I know the way to the bus station, but I do not know the way back.

Class 9 object marker -i- in ninaijua/siijui refers to njia. “Know a place” can mean know where it is, be familiar with its layout, or know it experientially; context supplies the precise relation.

Knowing how: infinitive complement

For an acquired ability or skill, kujua takes an infinitive:

Dada yangu anajua kuendesha gari, lakini hapendi kuendesha usiku.

My sister knows how to drive, but she does not like driving at night.

Watoto hao wanajua kuogelea kwa sababu wanaishi karibu na ziwa.

Those children know how to swim because they live near the lake.

The infinitives kuendesha and kuogelea are class 15 verb forms; they do not carry a separate finite subject because their understood actor is the knower. Unlike English, Swahili needs no word equivalent to “how” in this frame. See infinitive formation.

Knowing how is not the same as being able on one occasion. Anajua kuogelea says she has the skill; anaweza kuogelea leo says she can swim today, perhaps because conditions allow it. That contrast leads to kuweza.

💡

Use kujua + infinitive for learned competence and kuweza + infinitive for ability or possibility in the circumstances. The two overlap, but they answer different questions.

Sijui as a discourse formula

Literal sijui can stand as a complete answer:

— Basi litafika saa ngapi? — Sijui; ratiba haionyeshi muda.

— What time will the bus arrive? — I don't know; the timetable does not show a time.

It also introduces a tentative guess, often followed by labda “perhaps”:

Sijui, labda tukutane Alhamisi badala ya Jumatano.

I'm not sure; perhaps we should meet on Thursday instead of Wednesday.

This (informal) discourse use softens commitment. It does not necessarily mean the speaker lacks all relevant knowledge; it frames what follows as uncertain. In (formal) reporting, state the uncertainty more explicitly, for example haijathibitishwa kama... “it has not been confirmed whether...”

Kujua and kufahamu

Kujua is the unmarked broad verb: know a name, a person, a fact, a route, or a skill. Kufahamu often highlights grasping, understanding, or being informed about something and is frequent in (formal) explanation.

Ninafahamu masharti ya mkataba, lakini sijui tarehe ya malipo.

I understand the terms of the contract, but I don't know the payment date.

The distinction is not absolute: nafahamu can mean “I know/am aware,” and najua can imply deep familiarity. Collocation and intended emphasis decide; do not replace every English understand or know with the same Swahili verb mechanically.

Common combinations include kujua vizuri “know well,” kujua kwa hakika “know for certain,” kujua cha kufanya “know what to do,” and kutaka kujua “want to know.”

Common Mistakes

Keeping final -a in present negative

❌ Mimi sijua jibu la swali hilo.

Incorrect present-negative formation — jua changes final -a to -i.

✅ Mimi sijui jibu la swali hilo kwa sasa.

I do not know the answer to that question at present.

Omitting the human object marker

❌ Ninajua yule mwandishi binafsi.

Incorrect for the normal definite-human reading — index the known person with -m-.

✅ Ninamjua yule mwandishi binafsi kupitia dada yangu.

I know that writer personally through my sister.

Adding jinsi before a simple skill unnecessarily

❌ Anajua jinsi kuendesha baiskeli.

Incorrect complement shape — use an infinitive directly, or jinsi ya + infinitive.

✅ Anajua kuendesha baiskeli hata kwenye barabara yenye mteremko.

She knows how to ride a bicycle even on a sloping road.

Confusing learned skill with present possibility

❌ Hajui kuja leo kwa sababu anaumwa.

Incorrect for circumstantial inability — this says she lacks the skill of coming.

✅ Hawezi kuja leo kwa sababu anaumwa.

She cannot come today because she is ill.

Key Takeaways

The vowel-final stem gives ninajua, negative sijui, and subjunctive nijue.
Facts use a noun or a clause, often with kwamba; uncertainty uses kama “whether.”
Definite people normally trigger an object marker: unamjua?
Kujua + infinitive expresses knowing how; kuweza foregrounds ability or possibility.
Kufahamu often emphasizes comprehension or informed awareness, especially (formal).

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