Alipokuwa akila chakula cha mchana, alisikia simu ikilia.

Alipokuwa can be broken down like this:

• a- = he/she
• -li- = past tense
• -po- = when / at the time when
• -kuwa = be

So alipokuwa means something like when he/she was.

It is a very common kind of Swahili verb form where time information is built directly into the verb.

In Swahili, the subject is usually included in the verb itself.

So:

• alisikia = he/she heard
• alipokuwa = when he/she was
• akila = while he/she was eating

Because of the a- subject marker, you do not need a separate pronoun like yeye unless you want emphasis or contrast.

Akila means while he/she is eating or while eating.

It breaks down like this:

• a- = he/she
• -ki- = a marker often used for while, when, or simultaneous action
• -la = eat

So akila is a compact way to say while he/she was eating in this kind of sentence.

Why not anakula?
Because anakula is a normal present/progressive form: he/she is eating. In this sentence, akila fits better because it connects the action directly to another action happening at the same time.

Yes, both relate to time, but they do slightly different jobs.

• alipokuwa sets the time frame: when he/she was...
• akila gives the ongoing action during that time: eating

So alipokuwa akila is roughly like while he/she was eating.

It may feel a little repetitive if you compare it directly to English, but in Swahili this is a natural way to build a background action in a past narrative.

Literally, it means food of the daytime/noon.

• chakula = food / meal
• cha = of, agreeing with chakula
• mchana = daytime / noon / afternoon

So chakula cha mchana is the usual way to say lunch.

Cha is a connector meaning something like of.

It has to agree with the noun that comes before it. Since chakula belongs to a noun class that uses cha for this kind of connection, you get:

• chakula cha mchana = lunch
• literally meal of daytime

This kind of connector changes depending on noun class, so learners often need time to get used to it.

Alisikia means he/she heard.

It breaks down as:

• a- = he/she
• -li- = past tense
• -sikia = hear

So it is a straightforward past-tense verb: he/she heard.

Depending on context, kusikia can also sometimes mean to feel or to hear about, but here it clearly means to hear.

Simu ikilia means the phone ringing or as the phone was ringing.

Here:

• simu = phone
• i- = subject marker agreeing with simu
• -ki- = simultaneous action marker
• -lia = cry / sound / ring

After verbs of perception like see or hear, Swahili often uses this kind of -ki- form:

• Nilimwona akicheza = I saw him playing
• Alisikia simu ikilia = He/she heard the phone ringing

So ikilia works a bit like English ringing here.

Yes, -lia often means to cry, especially for people or babies.

But in Swahili it can also be used more broadly for making a sound, especially a sound like ringing or sounding.

So with simu, kulia means to ring.

This is normal and idiomatic:

• simu inalilia / inalia = the phone is ringing

So the idea is not that the phone is literally crying; it is just the natural Swahili verb here.

Because simu belongs to a noun class that takes i- as its singular subject marker.

So:

• simu ikilia = the phone ringing
• simu inalia = the phone is ringing

If the subject were plural, the agreement would change.

This is one of the important things in Swahili: verbs agree with the noun class of the subject, not just with person like in English.

The word order is natural and clear:

• background action first: Alipokuwa akila chakula cha mchana
• main event second: alisikia simu ikilia

This is similar to English sentences like While he was eating lunch, he heard the phone ringing.

You could rearrange it in some contexts, but the given order is especially common because it sets the scene first and then gives the main event.

It is natural and standard Swahili.

A speaker might also say something like:

• Wakati alikuwa anakula chakula cha mchana, alisikia simu ikilia.
• Alikuwa akila chakula cha mchana, alisikia simu ikilia.

These alternatives are also natural. The original sentence is a bit neat and textbook-friendly, but it is definitely real Swahili, not unnatural Swahili.

Yes. The exact English wording can vary a little:

• While he/she was eating lunch...
• When he/she was eating lunch...
• As he/she was eating lunch...

The Swahili mainly gives the idea of an ongoing background action during which another event happened. So all of those English versions are close, depending on style.