Mtoto alipolia usiku, mama alimchukua na kumbembeleza mpaka akalala.

Alipolia can be broken down as:

• a- = subject marker for a singular person/noun in class 1
• -li- = past tense
• -po- = a relative marker here meaning something like when
• -lia = cry

So alipolia means when he/she cried or when the child cried.

The -po- part is especially important here. It turns the verb into a time clause: at the time that the child cried.

Because Swahili verbs normally include a subject marker even when the subject noun is also written out.

So:

• Mtoto alipolia = literally something like child he/she-PAST-WHEN-cry
• Natural English: when the child cried

This is normal Swahili grammar. The noun mtoto and the subject marker a- go together.

Here usiku means at night or during the night.

Swahili often uses time words directly, without needing a preposition like English at or in. So:

• usiku = at night
• asubuhi = in the morning
• jana = yesterday

So alipolia usiku simply means when the child cried at night.

Alimchukua breaks down like this:

• a- = subject marker for a singular person, here mama
• -li- = past tense
• -m- = object marker for a singular person, here the child
• chukua = take, pick up

So alimchukua means she took him/her or, in this context more naturally, she picked the child up.

Because the object marker is -m-, the object is understood as a singular human being.

Na kumbembeleza is a compact way to continue the action with the same subject.

It consists of:

• na = and
• ku- = infinitive marker
• -m- = object marker, him/her
• bembeleza = soothe, coax, comfort gently

So literally it is something like and to soothe him/her, but in natural English it is best translated as and soothed him/her or and comforted him/her.

This structure is common in Swahili when one subject does a series of connected actions:

• alimchukua na kumbembeleza
  = she picked him/her up and comforted him/her

Kumbembeleza comes from bembeleza, which means to soothe, coax, pacify, comfort gently, or fuss over affectionately.

With a crying child, it suggests things like:

• holding the child
• rocking the child
• speaking softly
• trying to calm the child down

So kumbembeleza here is more than just talking. It gives a warm, gentle sense of comforting the child.

The object marker -m- refers to a singular person in noun class 1.

In this sentence, the most natural referent is mtoto.

So:

• alimchukua = she picked up the child
• kumbembeleza = to comfort the child

Swahili does not mark biological gender the way English does in pronouns, so -m- can mean him or her depending on context.

Mpaka means until or up to the point that.

So:

• mpaka akalala = until he/she fell asleep or until the child fell asleep

This gives the endpoint of the mother’s comforting. She kept comforting the child up to the moment the child finally slept.

Akalala is built with -ka-, which often links an event to what came before it in a sequence.

So:

• a-ka-lala = and then he/she slept / he/she eventually fell asleep
• a-li-lala = simple past, he/she slept

After a past action, -ka- is very common in narration to show the next resulting event. Here it fits the sense of:

• the mother picked the child up
• comforted the child
• and then, eventually, the child fell asleep

So mpaka akalala feels very natural in a story-like sequence.

In context, it is almost certainly the child.

Grammatically, a- in akalala could refer to either mama or mtoto, because both are singular class 1 nouns. But real-world meaning makes the child fell asleep the natural interpretation:

• the child cried
• the mother picked up the child
• the mother comforted the child
• the child fell asleep

If a speaker wanted to remove any possible ambiguity completely, they could make the subject explicit again.

Swahili does not have articles like English a/an and the.

So:

• mtoto can mean a child or the child
• mama can mean a mother or the mother

Which one is intended depends on context. In a sentence like this, English often uses the child and the mother, but Swahili does not need separate article words.

The sentence starts with the time clause:

• Mtoto alipolia usiku = When the child cried at night

Then it gives the main action:

• mama alimchukua na kumbembeleza mpaka akalala

This order is very natural because it sets the scene first.

Yes, Swahili can often vary word order for emphasis, but this version is especially clear and story-like:

1. the child cried at night
2. the mother responded
3. the child fell asleep

So the current order works very well for narration.