Learn Hardcore Swahili: Ni muhimu kuepuka kuchelewa shuleni. - It is important to avoid being late at school.

Ni – is / it is (copula; links the subject and description)
muhimu – important
kuepuka – to avoid (from verb epuka, with ku- infinitive marker)
kuchelewa – to be late / being late (from chelewa, with ku- infinitive marker)
shuleni – at school / in school (shule = school, -ni = locative “at/in”)

So very literally: Is important to-avoid to-be-late at-school.

Natural English: It is important to avoid being late to school.

Why does the sentence start with Ni muhimu and not something like Ina muhimu or Ni ya muhimu?

In Swahili, ni is commonly used as a copula meaning is / are / it is when linking a subject with a description (adjective, noun, etc.).

Ni muhimu literally = is important / it is important
You do not say ina muhimu here, because muhimu is not something a subject possesses; it’s a description. Kuwa na (to have) would not be used.
Ni ya muhimu would sound unnatural; muhimu already carries the idea “important” and doesn’t need ya in this construction.

So Ni muhimu is the standard way to say It is important.

Why is there no word for it in “It is important”? Where is the subject?

English uses a dummy subject it in sentences like:

It is important to study.
It is necessary to leave.

Swahili often doesn’t need such a dummy subject. The ni can stand alone as is / it is, and the real “content” of the sentence is the idea that follows.

You can think of it as:

Ni muhimu… → It is important… (general, impersonal statement)

The “subject” is really the whole idea kuepuka kuchelewa shuleni (avoiding being late to school), but Swahili doesn’t have to put an explicit it in front like English does.

What exactly are kuepuka and kuchelewa grammatically?

Both kuepuka and kuchelewa are verbs in their infinitive form, marked by the prefix ku-:

epuka → root verb meaning avoid
- kuepuka → to avoid / avoiding
chelewa → root verb meaning be late
- kuchelewa → to be late / being late

In Swahili, ku- + verb can function like:

an English infinitive: to avoid, to be late
or a gerund: avoiding, being late

So kuepuka kuchelewa = to avoid being late or avoiding lateness.

Why are there two infinitives in a row: kuepuka kuchelewa? Is that normal?

Yes, it’s normal. The structure is:

kuepuka X = to avoid X
Here, X is kuchelewa (shuleni) → being late (for school / at school)

So:

kuepuka kuchelewa shuleni = to avoid being late to school

Other similar patterns:

Ninajaribu kuelewa. – I am trying to understand.
Anaamua kuondoka. – He/She is deciding to leave.

In all of these, one verb (try, decide, avoid) is followed by another verb in the ku- form.

Can I say epuka kuchelewa shuleni without ku- on epuka?

Not in this sentence. Here’s why:

At the start of kuepuka kuchelewa shuleni, kuepuka is acting like an infinitive/gerund (to avoid / avoiding), not a finite verb.
epuka (without ku-) would normally be a stem you attach subject markers and tense to, e.g.:
- Ninaepuka – I avoid / I am avoiding
- Tuliepuka – We avoided

But in our sentence, we don’t want “I avoid” or “you avoid”; we want the general idea “to avoid”.

So:

Ni muhimu kuepuka kuchelewa shuleni. – correct
Ni muhimu epuka kuchelewa shuleni. – ungrammatical

What does the -ni in shuleni do? How is shule different from shuleni?

-ni is a locative suffix, often meaning in / at / on depending on context.

shule – school (as a noun)
shuleni – at school / in school

So in this sentence:

shule (alone) would just mean school.
kuchelewa shuleni = to be late at school / to be late to school.

You’ll see this pattern with other nouns too:

nyumba → nyumbani – house → at home
kanisa → kanisani – church → at church
duka → dukani – shop → at the shop

Could I say Ni muhimu kuepuka kuchelewa kwenye shule instead of shuleni? Is there a difference?

You can say kwenye shule, and people will understand you:

kuchelewa kwenye shule – to be late at school / to school

However:

shuleni is shorter and very natural in everyday Swahili.
For many common places (school, home, church, shop, etc.), the -ni locative is preferred and sounds more idiomatic.

So:

Ni muhimu kuepuka kuchelewa shuleni. – most natural
Ni muhimu kuepuka kuchelewa kwenye shule. – understandable but less typical in this context.

Can I change the word order to Kuepuka kuchelewa shuleni ni muhimu? Does it mean the same thing?

Yes, that word order is grammatically correct and means essentially the same thing:

Kuepuka kuchelewa shuleni ni muhimu.
Avoiding being late to school is important.

The difference is mainly one of emphasis:

Ni muhimu kuepuka kuchelewa shuleni.
Starts with the general idea “It is important…”.
Kuepuka kuchelewa shuleni ni muhimu.
Starts by highlighting the activity “Avoiding being late to school…” and then says it is important.

Both are fine; the first form (starting with Ni muhimu) is very common when giving general advice.

Is there another common way to say this idea, like using usichelewe?

Yes. A very natural alternative is:

Ni muhimu usichelewe shuleni.
It is important that you don’t arrive late at school.

Comparison:

Ni muhimu kuepuka kuchelewa shuleni.
- More abstract/general: “It is important to avoid being late to school.”
- No specific person is directly addressed.
Ni muhimu usichelewe shuleni.
- Uses usi- negative subjunctive: that you not be late.
- Sounds more like direct advice or instruction to you (singular) or you (plural) depending on context.

Both are correct; the original is a bit more impersonal and “principle-like.”

How would I change the tense, for example It was important or It will be important?

You change the copula part (ni) to match the time frame:

Ni muhimu kuepuka kuchelewa shuleni.
It is important to avoid being late to school. (present/general)
Ilikuwa muhimu kuepuka kuchelewa shuleni.
It was important to avoid being late to school.
(ili- = past marker for kuwa, to be)
Itakuwa muhimu kuepuka kuchelewa shuleni.
It will be important to avoid being late to school.
(ita- = future marker for kuwa)

Note: in the present, ni is sufficient; you don’t say inakuwa muhimu in this kind of general statement.