Usiku, mtoto anavaa pijama safi kabla ya kulala.

Here usiku means at night or in the evening/nighttime.

Swahili often puts a time expression at the beginning of the sentence to set the scene, just like English can do in sentences such as At night, the child....

So:

• Usiku, ... = At night, ...

It could also appear later in the sentence, but putting it first makes the time frame clear right away.

Mtoto means child and is gender-neutral. It can refer to either a boy or a girl.

That means the sentence itself does not tell you the child’s gender unless extra context is given.

Also:

• singular: mtoto = child
• plural: watoto = children

Anavaa can be broken down like this:

• a- = he/she (subject marker for singular human nouns like mtoto)
• -na- = present tense / habitual / ongoing
• -vaa = wear / put on

So anavaa literally means something like:

• he/she wears
• he/she is wearing
• he/she puts on

In this sentence, it most naturally means puts on or wears, depending on context.

This is a very common question.

• anavaa = puts on / wears / is putting on
• amevaa = is wearing / has put on

So:

• Mtoto anavaa pijama suggests the action of getting into pajamas, or a general routine.
• Mtoto amevaa pijama focuses on the result: the child already has the pajamas on.

In a bedtime routine sentence like this, anavaa fits well because it describes what the child does before sleeping.

Swahili does not use articles like English a, an, and the.

So:

• mtoto can mean a child, the child, or just child
• pijama can mean pajamas or the pajamas, depending on context

You figure out the exact meaning from the situation, not from an article.

Pijama is a loanword, from the same source as English pajamas/pyjamas.

In Swahili, pijama is commonly used as a clothing noun and often stays the same in form. In real use, speakers may treat it a bit like a fixed clothing word rather than worrying much about an English-style singular/plural distinction.

So in this sentence, pijama simply means pajamas / pyjamas.

In Swahili, adjectives usually come after the noun they describe.

So:

• pijama safi = clean pajamas

This is the normal order:

• noun + adjective

That is different from English, where adjectives usually come before the noun.

Some Swahili adjectives change to agree with the noun class, but safi is often used as an invariable adjective, meaning it stays the same.

So you get:

• nguo safi = clean clothes
• chumba safi = clean room
• pijama safi = clean pajamas

You do not need to change safi here.

Kabla ya kulala means before sleeping or before going to sleep.

It is made up of:

• kabla = before
• ya = of / for / linking word used in this expression
• kulala = to sleep / sleeping

So the whole phrase works like:

• before sleeping
• before going to bed

In Swahili, kabla is commonly followed by ya when it introduces a noun or infinitive phrase.

So you say:

• kabla ya chakula = before food
• kabla ya kazi = before work
• kabla ya kulala = before sleeping

This is just the normal pattern to learn:

• kabla ya + noun / infinitive

Kulala is the infinitive form of the verb -lala (sleep).

It breaks down as:

• ku- = infinitive marker, like English to
• -lala = sleep

So:

• kulala = to sleep

After kabla ya, this infinitive often translates naturally as an English -ing form:

• kabla ya kulala = before sleeping

No, the comma is not strictly necessary.

Both of these are fine:

• Usiku, mtoto anavaa pijama safi kabla ya kulala.
• Usiku mtoto anavaa pijama safi kabla ya kulala.

The comma just helps show a pause after the time expression, much like in English.

Yes, Swahili often allows the subject noun to be omitted if it is already clear from context, because the verb already includes a subject marker.

So:

• Mtoto anavaa pijama safi kabla ya kulala.
• Anavaa pijama safi kabla ya kulala.

Both are possible, but the first one is clearer if you are introducing the subject or emphasizing that it is the child who does this.

It can often be understood as a habitual action:

• At night, the child puts on clean pajamas before sleeping.

That is because the -na- tense in Swahili can cover present-time and habitual meanings, depending on context.

So anavaa here is very natural for describing a bedtime routine.