Jana, mimi nilisaidia kupalilia mpaka mikono ikachoka.

It has a very common Swahili structure:

• Jana = time expression, yesterday
• mimi = independent pronoun, I / me
• nilisaidia = main verb, I helped
• kupalilia = infinitive, to weed
• mpaka = until
• mikono = hands
• ikachoka = got tired

So the shape is roughly:

Time + subject pronoun + past verb + infinitive/action + until + second clause

The second clause, mikono ikachoka, gives the result or end point of the action.

Because ni- inside nilisaidia already marks the subject I, the word mimi is not required.

• Nilisaidia kupalilia... = perfectly correct, neutral
• Mimi nilisaidia kupalilia... = also correct, but more emphatic

Using mimi can suggest:

• emphasis: I helped
• contrast: I helped, maybe not someone else
• a slightly more deliberate or personal tone

So mimi is optional here.

Nilisaidia can be broken into parts:

• ni- = I
• -li- = past tense marker
• -saidia = verb root meaning help
• final -a = normal verb ending

So:

ni + li + saidia = nilisaidia
I + past + help = I helped

This is a very useful pattern in Swahili. For example:

• nilikula = I ate
• nilisoma = I read / studied
• nilifanya = I did

Because ku- is the infinitive marker, like to in English.

• palilia = weed
• kupalilia = to weed

After kusaidia / saidia, Swahili often uses an infinitive to show the action being helped with:

• nilisaidia kupika = I helped cook / I helped with cooking
• nilisaidia kubeba = I helped carry
• nilisaidia kupalilia = I helped weed / I helped with weeding

So kupalilia is the action connected to helped.

Kupalilia means to weed, especially removing weeds around crops or cultivated plants.

It is more specific than a general verb like kufanya kazi (to work) and different from:

• kulima = to farm / cultivate / dig
• kupanda = to plant
• kupalilia = to weed

So this sentence is talking about a particular farming or garden task.

Mpaka means until here.

It shows the limit or end point of the action:

• nilisaidia kupalilia = I helped weed
• mpaka mikono ikachoka = until my hands got tired

So the sense is:

I kept helping with the weeding to the point that my hands got tired.

In other contexts, mpaka can also mean up to, as far as, or even border, depending on the sentence.

Because the speaker wants to be specific about what got tired: the hands.

Compare:

• nilichoka = I got tired
• mikono ikachoka = my hands got tired

These are not exactly the same. The sentence with mikono focuses on physical strain in the hands from weeding.

This kind of expression is very natural in Swahili:

• miguu imechoka = the legs are tired
• macho yamechoka = the eyes are tired
• mikono ikachoka = the hands got tired

Ikachoka agrees with mikono and can be broken down like this:

• i- = subject marker for the noun class of mikono
• -ka- = a linking/consecutive marker, often giving a sense like and then, so, or a resulting next event
• -choka = become tired

So ikachoka is roughly:

they then got tired / they got tired as a result

Here they refers to mikono (hands), not to people.

This is an important point in Swahili: verbs agree with the noun class of the subject, not with English-style gender or person categories.

Swahili often leaves possession unstated when it is obvious from context.

In this sentence, the speaker is the one doing the work, so listeners naturally understand that these are the speaker’s hands.

So:

• mikono ikachoka = the hands got tired
• understood meaning: my hands got tired

If you want to make it explicit, you can say:

• mpaka mikono yangu ikachoka

That is also correct, but slightly more explicit or emphatic.

Yes. A more neutral version would be:

Jana nilisaidia kupalilia mpaka mikono ikachoka.

That is very natural.

About the commas:

• In writing, commas can show pauses or emphasis.
• In normal Swahili prose, they are often not necessary here.

So the commas are stylistic, not grammatical necessities.

Putting Jana first sets the time immediately. This is very common in Swahili.

It works a bit like saying:

• Yesterday, I helped weed...

You could also place it later:

• Mimi nilisaidia kupalilia jana...
• Nilisaidia kupalilia jana...

But Jana at the beginning sounds very natural because it frames the whole event from the start.

Yes, but the meaning changes.

• nilisaidia kupalilia = I helped with weeding
• nilipalilia = I weeded

So:

• Jana, mimi nilisaidia kupalilia... suggests you were helping with the task
• Jana nilipalilia... says you yourself did the weeding

The first sentence may imply cooperation with others or participation in a shared task. The second focuses directly on you as the one doing the weeding.

Mkono / mikono can refer to hand or arm, depending on context.

In this sentence, English will usually translate it as hands, because the action of weeding naturally involves the hands. But the broader Swahili word covers more than the strict English distinction.

So the sentence is natural even if English chooses the more specific word hands.