Negative -ku- or -ja-? | Swahili Grammar

Use negative-past -ku- to say that an event did not happen in a closed past frame. Use negative-perfect -ja- to say that an expected or relevant event has not happened up to the current point. Thus hakupiga simu jana means “she did not call yesterday,” while hajapiga simu bado means “she has not called yet.”

English speakers often choose by whether an English translation contains did not or has not. That shortcut fails in conversation, where English may use a simple past even though Swahili views the task as still pending. The decisive contrast is closed past denial versus open noncompletion.

The decision tree

Is there a closed past interval—yesterday, last Monday, during the former meeting, at a stated past hour? Choose negative -ku-.
Does the question ask what failed to occur in a past narrative? Choose -ku-.
Does the event remain expected, relevant, or possible now? Choose negative-perfect -ja-.
Can you naturally add bado “still/yet” or mpaka sasa “up to now”? That strongly favors -ja-.
Does a sentence mention both a past opportunity and the present pending state? Give each clause its own viewpoint: Sikuimaliza jana; bado sijaimaliza “I did not finish it yesterday; I still have not finished it.”

💡

Try two paraphrases: “During that past period, no event occurred” selects -ku-; “Up to now, the event remains incomplete” selects -ja-.

Both replace the affirmative prefix zone

Negative forms do not keep affirmative subject concord plus -li- or -me-. They use negative subject concord followed by the appropriate negative TAM marker.

Subject	Closed past with -ku-	Open perfect with -ja-
I	si-ku-som-a → sikusoma	si-ja-som-a → sijasoma
you (sg.)	hu-ku-som-a → hukusoma	hu-ja-som-a → hujasoma
he/she	ha-ku-som-a → hakusoma	ha-ja-som-a → hajasoma
we	hatu-ku-som-a → hatukusoma	hatu-ja-som-a → hatujasoma
you (pl.)	ham-ku-som-a → hamkusoma	ham-ja-som-a → hamjasoma
they	hawa-ku-som-a → hawakusoma	hawa-ja-som-a → hawajasoma

Both retain the default final -a of a productive -a verb. Neither uses the final -i of ordinary present negation. Any object marker follows the TAM marker: hatu-ku-i-som-a → hatukuisoma and hatu-ja-i-som-a → hatujaisoma.

For the complete formations and short-root behavior, see negative-past -ku- and negative-perfect -ja-.

-ku- denies an event inside a closed past frame

Negative-past -ku- answers questions about what did or did not happen at a past time. It is the negative counterpart of affirmative -li- even though the marker itself changes.

Sikuhudhuria kikao cha jana kwa sababu treni ilichelewa.

I did not attend yesterday's meeting because the train was delayed.

Wageni hawakulala hotelini Jumamosi; walikaa kwa ndugu zao.

The visitors did not sleep at the hotel on Saturday; they stayed with their relatives.

Jana and Jumamosi locate the denied events in completed intervals. The continuations give the alternative events in the same past story.

Hatukuitumia jenereta wakati umeme ulipokatika wiki iliyopita.

We did not use the generator when the electricity went out last week.

This is hatu-ku-i-tumi-a: negative first-person plural, negative past, class 9 object marker, and stem. The object marker remains beside the root exactly where the ordinary verb template predicts.

Negative -ku- does not mean “never” by itself. A past frame may be supplied by the surrounding narrative rather than an explicit adverb, but it must be recoverable.

-ja- leaves the event open up to now

Negative-perfect -ja- says that the relevant transition has not been completed by the current reference point. The event may still occur, or its absence may explain the current situation.

Mtoa huduma hajathibitisha nafasi yetu bado, kwa hiyo hatujalipa amana.

The service provider has not confirmed our booking yet, so we have not paid the deposit.

Barua hazijafika mpaka sasa; afisa wa posta anafuatilia mzigo.

The letters have not arrived up to now; the postal officer is tracing the shipment.

Bado and mpaka sasa make the open reference point explicit. The verb already contains negative-perfect meaning; bado remains a separate adverb, not another prefix.

Sijawahi kuendesha lori kubwa, lakini nina leseni ya kuanza mafunzo.

I have never driven a large truck, but I have a license to begin training.

With wahi, negative -ja- evaluates experience up to the present. There is no expected single truck journey here, but the lifetime window is still open.

💡

Bado is a powerful diagnostic, not part of the verb. Write bado hajamaliza or hajamaliza bado, never a fused form containing bado.

Matched pairs: identical event, different temporal question

Amina hakutuma fomu jana kabla ya ofisi kufungwa.

Amina did not submit the form yesterday before the office closed.

Amina hajatuma fomu bado, na muda wa mwisho ni kesho.

Amina has not submitted the form yet, and the deadline is tomorrow.

The first sentence closes the missed opportunity yesterday. The second checks completion against a deadline that remains open.

Sikupokea kifurushi Jumatatu, ingawa nilikuwa nyumbani siku nzima.

I did not receive the parcel on Monday, although I was home all day.

Sijapokea kifurushi mpaka sasa, lakini namba ya ufuatiliaji bado inafanya kazi.

I have not received the parcel up to now, but the tracking number still works.

Again the event is delivery. -Ku- evaluates Monday; -ja- evaluates the entire period ending now.

Dereva hakujaza mafuta kabla ya safari ya jana.

The driver did not fill the tank before yesterday's journey.

Dereva hajajaza mafuta; tusianze safari bado.

The driver has not filled the tank; let us not start the journey yet.

The second denial has an immediate practical result. Note the finished word hajajaza: ha-ja-jaz-a. Repeated syllables are legitimate when morpheme boundaries meet.

One sentence can need both

The two markers are not contradictory when each evaluates a different interval.

Sikuandika pendekezo jana, na bado sijaliandika kwa sababu data haijakamilika.

I did not write the proposal yesterday, and I still have not written it because the data is incomplete.

Si-ku-andik-a denies writing during yesterday. Si-ja-li-andik-a says the class 5 proposal remains unwritten now. This is the cleanest proof that the contrast is viewpoint, not merely two interchangeable negative past forms.

Time adverbs: strong cues and genuine ambiguity

Usually favors -ku-	Usually favors -ja-
jana — yesterday	bado — still/yet
wiki iliyopita — last week	mpaka sasa — up to now
mwaka 2020	hadi leo — through today
wakati wa kikao — during the meeting	hadi wakati huu — until this moment

An adverb does not select mechanically if its scope is unclear. Tangu jana sijamwona means “I have not seen him since yesterday”: jana names the beginning of a window that extends to now, so -ja- is appropriate. By contrast, Sikumwona jana asks only about yesterday and takes -ku-.

Tangu jana sijamwona Bakari ofisini; labda anafanya kazi nyumbani.

I have not seen Bakari at the office since yesterday; perhaps he is working from home.

This is a genuine ambiguous-looking case for English speakers. The preposition tangu changes jana from a closed interval into the starting point of an open one.

Short dialogue: move from yesterday to now

A: Uliisoma ripoti jana usiku? — B: Hapana, sikuipata jana.

A: Did you read the report last night? — B: No, I did not receive it yesterday.

A: Umeipata sasa? — B: Ndiyo, lakini bado sijaisoma; nitaisoma baada ya chakula.

A: Have you received it now? — B: Yes, but I still have not read it; I will read it after lunch.

The first exchange stays inside yesterday and uses si-ku-i-pat-a. The second checks present possession and pending reading, so it uses si-ja-i-som-a with bado.

Short roots do not add an extra support ku-

In a negative past, -ku- itself directly supports a short root: si-ku-l-a → sikula “I did not eat,” not sikukula. With negative-perfect -ja-, the corresponding form is si-ja-l-a → sijala “I have not eaten yet.”

Sikula asubuhi kwa sababu nilichelewa kuamka, na mpaka sasa sijala chochote.

I did not eat this morning because I woke up late, and up to now I have not eaten anything.

The paired short-root forms make both morphology and viewpoint visible.

Common Mistakes

Retaining affirmative -li- under negation

❌ Silipata ujumbe wako jana.

Incorrect — negative past replaces affirmative ni-li- with si-ku-.

✅ Sikupata ujumbe wako jana kwa sababu simu ilikuwa imezimwa.

I did not receive your message yesterday because the phone was switched off.

Using -ku- for a task still pending now

❌ Bado hatukumaliza hesabu za mwezi huu.

Wrong viewpoint for an unfinished task extending to now.

✅ Bado hatujamaliza hesabu za mwezi huu.

We have not finished this month's accounts yet.

Using -ja- for a closed dated denial

❌ Hawajafungua duka Jumapili iliyopita.

Incorrect for a simple report about last Sunday — the frame is closed.

✅ Hawakufungua duka Jumapili iliyopita kwa sababu kulikuwa na matengenezo.

They did not open the shop last Sunday because repairs were underway.

Changing final -a to -i

❌ Mwanafunzi hajaandiki ripoti bado.

Incorrect — negative-perfect -ja- retains the verb's default final -a.

✅ Mwanafunzi hajaandika ripoti bado; mwalimu asubiri kidogo.

The student has not written the report yet; the teacher should wait a little.

Adding support ku- to a negative-past short root

❌ Sikukula chakula cha jioni jana.

Incorrect — negative-past -ku- already supports the short root -l-.

✅ Sikula chakula cha jioni jana kwa sababu nilikuwa safarini.

I did not eat dinner yesterday because I was traveling.

Key Takeaways

Negative -ku- denies an event in a closed past interval.
Negative-perfect -ja- says that an event remains incomplete up to the current point.
Bado, mpaka sasa, and hadi leo strongly favor -ja-; closed dates strongly favor -ku-.
Both patterns use negative subject concord and retain the default final -a.
The same discourse can use both forms when it contrasts a missed past opportunity with a task still pending now.

Now practice Swahili

Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.

Start learning Swahili →