Learn Hardcore Swahili: Watoto wanapenda kutania wenzao wakati wa mapumziko. - Children like to tease their friends during break time.

So structurally it is similar to English “Children like to tease their friends during break time.”
The main difference is that tense and subject are built into the verb form (wanapenda), rather than using a separate word like they + like.

What exactly does wanapenda mean, and how is it built?

Wanapenda means “(they) like / love” or “(they) enjoy.”

It is made of three parts:

wa- – subject prefix for they (plural people, matching watoto)
-na- – present tense marker (often used for present/habitual)
penda – verb root meaning like / love

So:

wa- + -na- + penda → wanapenda = they-like (present)

Because the subject “they” is already inside wanapenda (wa-), you don’t need a separate word for they; watoto gives the noun, and the verb agrees with it.

What does kutania mean, and why does it start with ku-?

Kutania means “to tease / to joke with someone”.

In Swahili, the infinitive / verbal noun is formed with ku- + verb root:

tania – tease / joke with
ku- + tania → kutania – to tease / teasing

In this sentence, kutania functions much like English “to tease” or “teasing” after “like”:

wanapenda kutania – they like to tease / they like teasing

What is the difference between kutania and utani? Could I say Watoto wanapenda utani?

Kutania is a verb form (infinitive): to tease / teasing.
Utani is a noun: joking, teasing, a joke, banter.

Both are possible, but they sound slightly different:

Watoto wanapenda kutania wenzao.
– Children like to tease their friends.
Focus: the action of teasing others.
Watoto wanapenda utani.
– Children like jokes / joking / banter.
Focus: jokes / joking as a thing or general activity, not necessarily directed specifically at their friends.

In your original sentence, kutania wenzao makes it explicit that they are teasing their peers.

What exactly does wenzao mean, and how is it formed?

Wenzao means roughly “their peers / their mates / their fellows.”

It comes from:

mwenza – companion, colleague, partner, mate (singular)
wenza – plural companions / peers
-o from wao – their (3rd person plural possessive), attached as a suffix

So:

wenza + (wa)o → wenzao = their companions / their peers

In context with watoto, wenzao is best understood as “their fellow children / their classmates / their friends.”

How is wenzao different from saying marafiki zao?

Both can translate as “their friends,” but the nuance is different:

wenzao – their peers / fellows / mates
- More general: people of the same group, status, class, age, team, etc.
- Does not necessarily imply close friendship; it could be classmates, schoolmates, colleagues.
marafiki zao – their friends
- From rafiki (friend) → marafiki (friends) + zao (their).
- Emphasises friendship more explicitly.

So:

Watoto wanapenda kutania wenzao.
– They like teasing their peers / other kids (in general).
Watoto wanapenda kutania marafiki zao.
– They like teasing their friends (more explicitly about friends, not just any peers).

Why is watoto used without an article like “the” or “some”?

Swahili does not have articles like “a / an / the”.
A noun like watoto can mean:

children
the children
some children
children in general

Context decides the best translation.

Here, Watoto wanapenda… is a general statement about children as a group, so natural English is:

“Children like to tease their friends…” (generic)
You could also translate it as “The children…” if the context is specific, but Swahili itself does not mark the difference with an article.

What does wakati wa mapumziko literally mean, and why do we use wa?

Literally:

wakati – time, period, moment
wa – possessive/connector of
mapumziko – rest, break, break time

So wakati wa mapumziko is “time of break(s)”, i.e. “during break time” / “at break.”

The wa is a possessive/connecting marker that agrees with wakati and means “of.”
So:

wakati wa mapumziko → the time of break(s) → during the break

Could I also say katika mapumziko instead of wakati wa mapumziko?

Yes, you could say katika mapumziko, but the nuance is slightly different:

wakati wa mapumziko – literally the time of the break(s) → natural English: “during break time.”
Focuses on the time period.
katika mapumziko – literally in (the) break(s) → “in the break / during the break.”
Grammatically fine; often also understood as “during the break.”
It feels a bit more like “in the period of break”, and can be slightly less idiomatic in some contexts than wakati wa mapumziko, which is very standard.

In many everyday situations, both will be understood as “during break time.”

What noun classes are mtoto / watoto and mwenza / wenzao, and how does that affect the sentence?

Both sets belong to the people noun classes (1/2), which use m-/wa-:

mtoto (child) → singular, class 1
watoto (children) → plural, class 2
mwenza (companion/peer) → singular, class 1
wenza (companions/peers) → plural, class 2
- -o from wao → wenzao (their peers)

Because watoto is class 2 (plural people), the verb must use the class 2 subject prefix wa-:

wa- + -na- + penda → wanapenda

If the subject were singular (mtoto), the verb would change:

Mtoto anapenda kutania wenzao.
– The child likes to tease their peers.
(a- is the singular subject prefix for class 1.)

What kind of time meaning does wanapenda have here – is it a general habit or something happening right now?

The -na- tense in wanapenda is usually:

present / present continuous, and very often
habitual (something that happens regularly)

In this context, with no specific time word like sasa (now), it’s most naturally:

habitual / general truth: Children (generally) like to tease their friends during break.

To make it clearly “right now,” Swahili usually adds a time adverb:

Watoto wanapenda kutania wenzao sasa hivi.
– The children are (right now) enjoying teasing their friends.

How would I change the sentence to say “The children are teasing their friends during break” (not just “like to tease”)?

You want to focus on the action happening now, not on what they like.
So you remove wanapenda (“like”) and use the verb kutania directly as the main verb:

Watoto wanawatania wenzao wakati wa mapumziko.

Breakdown:

Watoto – the children
wana-…-tania – they are teasing
- wa- (they) + -na- (present) + tania (tease)
wa- inside wanawatania is also an object marker:
- wana-wa-tania → they-are-them-teasing = they are teasing them
wenzao – their peers/friends
wakati wa mapumziko – during break

So:

Watoto wanawatania wenzao wakati wa mapumziko.
= The children are teasing their friends during break.