Learn Hardcore Swahili: Watoto wenyewe waliamua kuosha vyombo baada ya chakula cha jioni. - The children themselves decided to wash the dishes after dinner.

Watoto waliamua kuosha vyombo...
= The children decided to wash the dishes…
Watoto wenyewe waliamua kuosha vyombo...
= The children themselves decided to wash the dishes (no one else told them / it was their own decision).

So wenyewe highlights that:

they did it by themselves (no help), or
it was their own decision (not forced),
depending on context. Here, it leans toward “by their own decision / initiative.”

Is wenyewe always used right after the noun, like in watoto wenyewe?

For the meaning “the X themselves,” it usually comes immediately after the noun:

walimu wenyewe – the teachers themselves
wazazi wenyewe – the parents themselves
watoto wenyewe – the children themselves

If you move wenyewe somewhere else, it can change what is being emphasized. For example:

Watoto wenyewe waliamua kuosha vyombo.
Focus: it was the children (not other people) who decided.
Watoto waliamua kuosha vyombo wenyewe.
Focus: they washed the dishes themselves (without help), not necessarily that they were the only ones making the decision.

So its position helps you choose whether you’re stressing:

who did/decided (put it right after the noun), or
how they did it (put it later, after the verb phrase).

How is the verb waliamua formed, and what exactly does it tell us?

Waliamua can be broken down as:

wa- = subject prefix for “they” (3rd person plural, noun class 2 people, e.g. watoto)
-li- = past tense marker (simple past)
-amua = verb stem “decide”

So waliamua literally is “they-PAST-decide” → they decided.

Other possible tenses with the same verb:

wanaamua – they are deciding / they decide (present)
wataamua – they will decide (future)
wameamua – they have decided (recent/completed action relevant now)

Why do we need ku- in kuosha after waliamua? Why not just say waliamua osha vyombo?

After verbs like amua (decide), anza (start), jaribu (try), etc., Swahili typically uses the infinitive form of the second verb, which starts with ku-:

kuosha – to wash
kusoma – to read / study
kula – to eat

So:

waliamua kuosha vyombo – they decided to wash the dishes
waliamua kusoma – they decided to study

You cannot drop the ku- here; waliamua osha vyombo is ungrammatical.

What’s the difference between kuosha vyombo and something like kuviosha?

Both are built from -osha (wash), but they work differently:

kuosha vyombo
- kuosha = to wash
- vyombo = dishes/utensils
- This is the neutral, normal way when you actually mention the noun.
kuviosha
- ku- = infinitive marker
- -vi- = object prefix for class 8 (plural, vyombo)
- -osha = wash
- This means to wash them, referring back to something already known from context.

So you would typically use:

waliamua kuosha vyombo – they decided to wash the dishes.
waliamua kuviosha – they decided to wash them (no need to repeat vyombo).

Using both together (kuviosha vyombo) is usually redundant and not natural unless used for a special emphasis.

What exactly does vyombo mean here, and what is its singular form?

In this context, vyombo means dishes / utensils / crockery — things you wash after eating (plates, cups, cutlery, pots, etc.), not just plates.

Singular: chombo – a vessel, container, tool, or instrument
Plural: vyombo – vessels, utensils, tools, instruments

So:

kuosha vyombo – to wash the dishes / utensils

Depending on context, chombo/vyombo can also mean instruments (e.g., vyombo vya muziki – musical instruments), but here the context is clearly kitchen/dining.

Why do we have both ya and cha in baada ya chakula cha jioni? Don’t they both mean “of”?

Yes, both ya and cha are possessive/genitive connectors (“of”), but they agree with different head nouns:

baada ya chakula
- baada = after
- ya = “of” agreeing with baada (which behaves like a class 9/10 noun)
- literally “after of the food” → after the meal/food
chakula cha jioni
- chakula = food/meal (class 7)
- cha = “of” agreeing with chakula (class 7)
- jioni = evening
- literally “food of evening” → evening meal / dinner

Combine them:

baada ya chakula cha jioni
= after the evening meal / after dinner.

So:

ya agrees with baada
cha agrees with chakula

Could we just say baada ya chakula instead of baada ya chakula cha jioni?

Yes, you can say:

Watoto wenyewe waliamua kuosha vyombo baada ya chakula.

That simply means “The children themselves decided to wash the dishes after the meal.”

The version with cha jioni is more specific:

chakula – a meal (any meal)
chakula cha jioni – the evening meal (dinner/supper)

So both are correct; the longer phrase just gives you the time of day.

Why is it chakula cha jioni and not chakula ya jioni?

Because chakula is a class 7 noun (ki/vi class: kitu/vitu, chakula/vyakula, etc.), and possessive/genitive connectors must agree with the noun class:

Class 7 → cha
Class 8 → vya
Class 9/10 → ya, etc.

So:

chakula cha jioni – food of evening → dinner
kitu cha mtoto – the child’s thing
kisu cha jikoni – the kitchen knife

Ya would be used if the head noun were a class 9/10 noun, e.g.:

saa ya jioni – evening hour/time
nguo ya jioni – evening dress

Where could I put the time phrase baada ya chakula cha jioni in the sentence? Is the current position the only correct one?

Swahili word order is quite flexible with time expressions. These are all natural, with slight differences in emphasis:

Watoto wenyewe waliamua kuosha vyombo baada ya chakula cha jioni.
(Neutral: describes what they did, then when.)
Baada ya chakula cha jioni, watoto wenyewe waliamua kuosha vyombo.
(Emphasis on when it happened: “After dinner, the children themselves…”)
Watoto wenyewe, baada ya chakula cha jioni, waliamua kuosha vyombo.
(Extra emphasis or a more “storytelling” rhythm.)

All are grammatical. Putting the whole time phrase at the start (Baada ya chakula cha jioni…) is very common in narrative and conversation.

Does wenyewe here mean they washed the dishes themselves, or that they decided by themselves?

In this specific sentence:

Watoto wenyewe waliamua kuosha vyombo...

The structure places wenyewe right after watoto, so the most direct reading is:

The children themselves decided (not parents, not guests, etc.).

If you wanted to emphasize that they did the washing by themselves (without help), you’d more naturally put wenyewe nearer to the verb phrase:

Watoto waliamua kuosha vyombo wenyewe.
= The children decided to wash the dishes themselves (no help).

Context can still make both shades of meaning possible, but position strongly suggests whether the focus is on:

who decided (watoto wenyewe), or
who did the work (vyombo wenyewe / verb + wenyewe).