Nilipokuwa nikimenya viazi na boga, mtoto alikuwa akiniangalia jikoni.

They work together, but they do different jobs.

• nilipokuwa = when I was
• nikimenya = peeling

So Nilipokuwa nikimenya... literally breaks down as something like:

• ni- = I
• -li- = past
• -po- = when
• -kuwa = be

So nilipokuwa means when I was.

Then:

• niki- = I ... while/ongoing
• -menya = peel

So nikimenya means while I was peeling or peeling in an ongoing sense.

Together, the whole part means when I was peeling. Swahili often uses this kind of layered structure where English would just use one past continuous form.

In this sentence, -po- gives the sense of when.

So:

• nilikuwa = I was
• nilipokuwa = when I was

This -po- is often called a relative marker of time/place depending on context, but for a learner, the useful takeaway is:

• nilipokuwa = when I was
• alipokuwa = when he/she was
• tulipokuwa = when we were

It is a very common pattern in storytelling and description.

Because the action is ongoing in the background.

Compare:

• nilimenya viazi = I peeled potatoes / I peeled the potatoes
  This sounds like a completed past action.

• nilikuwa nikimenya viazi = I was peeling potatoes
  This clearly shows an ongoing action in the past.

• nilipokuwa nikimenya viazi... = when I was peeling potatoes...
  This sets the scene for another action.

So nikimenya is the form that matches the idea of was peeling or while peeling.

Because alikuwa akiniangalia means was watching me, while aliniangalia means watched me.

Compare:

• mtoto aliniangalia = the child watched/looked at me
• mtoto alikuwa akiniangalia = the child was watching me

In your sentence, both actions are presented as ongoing at the same time:

• I was peeling
• the child was watching me

That is why the longer progressive-style form is used.

It breaks down like this:

• a- = he/she
• -ki- = ongoing/while
• -ni- = me
• -angalia = look at / watch

So akiniangalia means he/she watching me or, in smoother English, watching me.

In the full phrase:

• mtoto alikuwa akiniangalia = the child was watching me

The important part for many learners is the object marker:

• -ni- = me

So:

• ananiangalia = he/she is watching me
• akiniangalia = he/she while watching me / watching me in this progressive construction

That -ni- is the object marker meaning me.

Swahili verbs can include the object inside the verb:

• anakusikia = he/she hears you
• anampenda = he/she loves him/her
• akiniangalia = he/she is watching me

So instead of using a separate word for me, Swahili often builds it into the verb.

Yes, but they are not exactly the same.

• kuona = to see
• kuangalia = to look at / to watch

In this sentence, the child was watching me, not just passively seeing me. That is why kuangalia fits better.

So:

• aliniwona = he/she saw me
• aliniangalia = he/she looked at me / watched me

Jikoni means in the kitchen.

The ending -ni often marks location.

So:

• jiko = stove / cooking place
• jikoni = in the kitchen / at the kitchen area

More generally, -ni is very common in location words:

• nyumbani = at home
• shuleni = at school
• mezani = on the table / at the table

Here jikoni tells you where the action was happening.

That is a normal and natural place for it. Swahili word order is fairly flexible, but a common order is:

• subject
• verb
• object
• place

So:

• mtoto alikuwa akiniangalia jikoni

literally follows a pattern like:

• the child
  • was watching me
    • in the kitchen

You could move some parts for emphasis in certain contexts, but the sentence as given sounds very natural.

It can mean either, depending on context.

Swahili does not have articles like a, an, and the. So:

• mtoto can be a child
• mtoto can also be the child

The surrounding context tells you which one is meant.

That is very normal in Swahili. Many nouns work this way.

Viazi is one of those nouns that learners just have to get used to.

In everyday Swahili, viazi commonly refers to potatoes. Depending on context, it can sometimes refer to potato pieces or potatoes in a general sense, not just a neat English-style countable plural.

A useful practical takeaway is:

• viazi = potatoes
• viazi vikuu = Irish potatoes / regular potatoes
• viazi vitamu = sweet potatoes

You do not need to over-analyze it every time you see it; just learn viazi as the normal word for potatoes.

Boga usually means pumpkin or squash/gourd, depending on region and context.

So viazi na boga means potatoes and pumpkin/squash.

If the translation you were shown says one or the other, that is probably just choosing the most natural English word for the context.

Yes.

In viazi na boga, na simply means and:

• viazi na boga = potatoes and pumpkin/squash

But remember that na can also mean with in other contexts:

• ninaenda na mtoto = I am going with the child

So na is a very common word with a couple of related meanings.

Yes. Even if the core meaning stays the same, several English versions are natural:

• When I was peeling potatoes and pumpkin, the child was watching me in the kitchen.
• While I was peeling potatoes and squash, the child was watching me in the kitchen.
• As I was peeling potatoes and pumpkin, the child was watching me in the kitchen.

That is normal. Swahili and English do not always match one-for-one, especially with continuous actions and words like boga.

A helpful way to see it is:

• Nilipokuwa nikimenya viazi na boga = When I was peeling potatoes and pumpkin
• mtoto alikuwa akiniangalia jikoni = the child was watching me in the kitchen

So the sentence has:

1. a background time clause
2. a main clause

This is a very common storytelling pattern in Swahili:

• When X was happening, Y was happening.

That is why the sentence feels rich in verb forms: it is describing two simultaneous ongoing past actions.