Learn Hardcore Swahili: Watoto hulala mapema siku za shule, lakini wikendi hulala kuchelewa. - Children sleep early on school days, but on weekends they sleep late.

Watoto hulala mapema…
Uses hu-, the habitual marker. It tells you this is a regular, typical habit or general fact:
Children usually/typically sleep early…
Watoto wanalala mapema…
Uses wa- (they) + -na- (present) + -lala (sleep). This can mean:
- They are sleeping early (right now / these days), or
- They sleep early (also possible for habits, depending on context).

In practice:

hulala sounds more like a general rule or established routine.
wanalala often feels more like what is happening now or in this period, though with adverbs like kila siku it can also describe habits.

So the sentence with hulala strongly emphasizes a usual pattern: this is what the kids normally do on school days and weekends.

Why is there no subject marker on hulala (why not Watoto wanahulala or something similar)?

With the habitual hu-, Swahili does not use a separate subject prefix on the verb.

Compare:

Normal present: wa-na-lala → wanalala
- wa- = they (subject)
- -na- = present tense
- -lala = sleep
Habitual: hu-lala → hulala
- hu- = habitual tense (also takes over the slot where the subject prefix would go)
- -lala = sleep

When you use hu-, you do not attach wa-, ni-, u- etc. before the verb. The subject is either:

Understood from context, or
Given as a noun or pronoun before the verb, like Watoto hulala…

So forms like wahulala or wanahulala are ungrammatical in standard Swahili. The correct pattern is simply:

Mimi hulala… (I usually sleep…)
Watoto hulala… (Children usually sleep…)

What is the difference between hu- in hulala and ku- in kuchelewa?

hu- and ku- are two completely different things:

hu- in hulala
- This is a tense/aspect marker meaning “usually / habitually”.
- It replaces the normal tense (-na-, -li-, -ta-, etc.) and the subject prefix on the verb.
ku- in kuchelewa
- This is the infinitive prefix (like to in English to sleep, to be late).
- kuchelewa literally = to be late / being late.
- After another verb, ku- often turns the verb into something like a verbal noun or an adverbial phrase.

So:

hulala ≈ (subject) usually sleeps
kuchelewa ≈ to be late / late-ness (functioning here like “late” in “sleep late”)

What part of speech is mapema, and why don’t we say something like kwa mapema?

mapema is an adverb meaning early.

It modifies the verb hulala: Watoto hulala mapema = The children sleep early.

Unlike English, Swahili does not need a preposition like at or in in front of many time adverbs. So you say:

Anaondoka mapema – He/She leaves early
Tutafika mapema – We will arrive early

You do not normally say kwa mapema for simple “early” in time. mapema on its own is the natural form.

What exactly does siku za shule mean, and why is it za instead of ya?

siku za shule literally means days of school, i.e. school days.

Breakdown:

siku – day / days
- It belongs to the N-class (same form for singular and plural).
za – “of” for N-class plural nouns
shule – school (also N-class)

So:

siku za shule = days of school → “school days”

The za is required because:

For one day of school: siku ya shule (day of school) – singular → ya
For several days: siku za shule (days of school) – plural → za

Thus, za agrees with siku as a plural N-class noun.

In English we say “on school days” or “on weekends”. Why is there no word for “on” in siku za shule or wikendi?

Swahili usually does not use a preposition like “on” before expressions of time such as days, dates, or general periods.

You simply put the time phrase directly:

Siku za shule – (on) school days
Jumatatu – (on) Monday
Usiku – (at) night
Wikendi – (on) weekend / on weekends

So in your sentence:

Watoto hulala mapema siku za shule
= Children sleep early on school days.
…lakini wikendi hulala kuchelewa.
= …but on weekends they sleep late.

If you really want to be more explicit, you can use phrases like wakati wa… (during…), but it’s not needed here.

What is wikendi exactly? Is it a Swahili word, and is it singular or plural?

wikendi is a loanword from English weekend. It behaves like an N-class noun:

Same form for singular and plural: wikendi can mean weekend or weekends, depending on context.
In your sentence, wikendi clearly means weekends in general (a recurring time).

Common alternatives in Swahili:

mwishoni mwa wiki – at the end of the week (often = the weekend)
siku za wikendi – the days of the weekend
Informally: jumamosi na jumapili – Saturday and Sunday

So wikendi hulala kuchelewa = On weekends, (they) sleep late.

Could we also say siku za wikendi instead of just wikendi?

Yes, you can say siku za wikendi, and it is understandable and correct:

Watoto hulala mapema siku za shule, lakini siku za wikendi hulala kuchelewa.
= Children sleep early on school days, but on weekend days they sleep late.

The difference is mainly style and brevity:

wikendi hulala kuchelewa – shorter, natural, common in speech.
siku za wikendi hulala kuchelewa – a bit more explicit (“on the weekend days”), but also fine.

What does kuchelewa literally mean, and how does hulala kuchelewa end up meaning “sleep late”?

The root verb chelewa means to be late.

kuchelewa = to be late / being late / lateness (infinitive / verbal noun)

In hulala kuchelewa, the second verb kuchelewa functions like an adverbial complement, describing how they sleep:

Watoto hulala kuchelewa.
Literally: The children usually sleep (with) being late.
Idiomatically: The children usually sleep late.

So kuchelewa here is not “they are late” as a separate action; it’s modifying hulala, just like an adverb:

hulala mapema – sleep early
hulala kuchelewa – sleep late

Note: kuchelewa implies being late compared to a normal/expected time, not just “later than before” (where you might use baadaye).

Why is kuchelewa in the infinitive form? Could I say something like …lakini wikendi wanachelewa instead?

In hulala kuchelewa, kuchelewa is in the infinitive because it is working like an adverbial/verbal noun attached to hulala — it tells us in what way they sleep.

If you say:

…lakini wikendi wanachelewa.

you change the meaning to something like:

…but on weekends they are late.

That sounds like they are late for something (e.g., late to school, late to an appointment), not that they sleep late.

So:

wikendi hulala kuchelewa – On weekends they sleep late.
wikendi wanachelewa – On weekends they are (arriving/doing something) late.

For the idea of “sleep late”, Swahili naturally uses a structure like kulala kuchelewa.

Do we have to repeat hulala in the second part, or could we just say …lakini wikendi kuchelewa?

You really should keep a full verb form in the second clause:

…lakini wikendi hulala kuchelewa.

If you say just …lakini wikendi kuchelewa, it sounds incomplete in Swahili — more like a fragment: “…but on weekends, being late” without a clear main verb.

However, you do not need to repeat watoto:

Watoto hulala mapema siku za shule, lakini wikendi hulala kuchelewa.
= Children sleep early on school days, but (they) sleep late on weekends.

This is natural: you keep hulala because each clause needs its own finite verb, but you can drop the subject noun in the second clause once it’s clear from context.