Learn Hardcore Swahili: Nilimtumia bibi ujumbe wa sauti jana usiku kupitia simu janja. - I sent grandmother a voice message last night via smartphone.

Using the object marker -m-:
- Sounds more natural when you are talking about a specific, known person.
- Helps keep track of who is receiving what, especially in longer sentences.
- Is very typical with human objects (people, relatives, etc.).

So it’s not “wrong” redundancy; it’s normal agreement and a sign of definiteness/importance.

In Nilimtumia bibi ujumbe wa sauti, which noun is the direct object and which is the indirect object?

bibi is the indirect object: the person to whom something is sent.
ujumbe wa sauti is the direct object: the thing that is sent (a voice message).

The typical Swahili pattern is:

Subject–Verb–Indirect object–Direct object

So:

Nilimtumia bibi ujumbe wa sauti
= I sent grandmother a voice message.

You could also say:

Nilimtumia ujumbe wa sauti kwa bibi.

Here kwa bibi is a prepositional phrase (to grandmother), and ujumbe wa sauti is clearly the direct object.

Why is it tumia and not just tuma in Nilimtumia?

There are two things going on:

tuma = to send.
There is an applicative suffix -ia, which often means do X to/for someone.

So:

tuma → send
tum-ia → send to / send for (someone)

This gives tumia in the sense send to someone.

So:

Nilimtuma (from tuma only) = I sent him/her (as a messenger / dispatched them).
Nilimtumia bibi ujumbe (from tuma + -ia) = I sent grandmother a message (i.e. I sent something to her).

In real life, people usually use mtumia for send someone something.

But I learned tumia means “use”. Doesn’t Nilimtumia also mean “I used him/her”?

Yes, there is also an independent verb tumia meaning to use:

kutumia pesa = to use/spend money
Ninatumia simu janja = I use a smartphone

So mechanically:

Nilimtumia can be:
- from tuma + -ia → I sent to him/her, or
- from tumia (use) → I used him/her.

In practice, context clears this up immediately. In a sentence with ujumbe wa sauti, speakers will understand the “send to” meaning, not “used her”.

So yes, the forms overlap, but speakers don’t get confused because the surrounding words tell you which verb is intended.

What exactly does bibi mean? Is it only “grandmother”?

bibi has several common meanings, depending on region and context:

Grandmother – very common everyday meaning.
Mrs. / Ms. / Lady / Ma’am – a respectful title for a woman.
Wife – in some dialects or older usage.

To be clearer, people often say:

bibi yangu = my grandmother (or my wife, context-dependent)
nyanya = grandmother (in some regions, especially in Tanzania)
mke wangu = my wife (unambiguous)

In your sentence, the meaning has already been given to the learner, but in general, bibi is a respectful word for an older woman or a grandmother, and may also be used in other polite or regional senses.

Why is it ujumbe wa sauti and not something like ujumbe sauti?

Swahili usually links two nouns with a genitive connector that agrees with the noun class of the first noun:

ujumbe is class 3/4, which uses wa for “of”.

So:

ujumbe wa sauti = message of sound → voice message
jina la mtoto = name of the child
mlango wa nyumba = door of the house

You almost always need this connector (like wa, la, ya, cha, vya, za, kwa, kwa etc.), not just two nouns next to each other.

Does wa always stay the same, or does it change with different nouns?

It changes to match the noun class of the first noun:

Some common patterns:

Class 1/2 (mtu / watu): wa
- rafiki wa mtoto = the child’s friend
Class 3/4 (mti / miti, ujumbe / ujumbe): wa
- ujumbe wa sauti = voice message
Class 5/6 (tunda / matunda): la / ya
- tunda la embe = mango fruit
Class 7/8 (kitu / vitu): cha / vya
- kitabu cha Kiswahili = a Swahili book
Class 9/10 (simu / simu): ya / za
- simu ya nyumbani = home phone

So wa appears with some classes (like 1/2 and 3/4), but other classes use different connectors.

What does jana usiku literally mean, and can the order change?

Literally:

jana = yesterday
usiku = night

So jana usiku = yesterday night, i.e. last night.

Other possible expressions:

usiku wa jana = the night of yesterday (also “last night”)
jana alone can sometimes imply “yesterday (during the day)”, so adding usiku makes it clear you mean at night.

On position in the sentence:

Time expressions can go at the beginning:
- Jana usiku nilimtumia bibi ujumbe wa sauti.
Or after the verb phrase, as in your sentence:
- Nilimtumia bibi ujumbe wa sauti jana usiku.

Both are natural.

What does kupitia simu janja mean, and are there simpler alternatives?

kupitia here means “through / via / by means of”.

kupitia simu janja = through a smartphone / via smartphone.

Other common ways to express this idea:

kwa simu = by phone
kwa kutumia simu janja = by using a smartphone
kwa njia ya simu janja = by means of a smartphone

So you could also say:

Nilimtumia bibi ujumbe wa sauti jana usiku kwa simu. = I sent grandma a voice message last night by phone.

What does simu janja literally mean, and is that the only word for “smartphone”?

Literally:

simu = telephone / phone
janja = clever, crafty, smart

So simu janja = smart phone (a clever phone).

Other terms you may see:

simu mahiri – another coined term for smartphone
simu ya mkononi – mobile / cell phone (not necessarily “smart”)
Colloquially many people just say simu and context tells you it’s a smartphone.

But simu janja is a widely understood, standard way to say smartphone.

How would I change the sentence if I want to say “She sent me a voice message last night via smartphone”?

Starting from the pattern:

Subject–Tense–Object–Verb stem–indirect object–direct object–time–means

We want:

Subject: she → a-
Object: me → -ni-
Verb: tumia (send to)
Indirect object (sender) is the subject; recipient is in the object marker.
Direct object: ujumbe wa sauti
Time: jana usiku
Means: kupitia simu janja

The sentence:

Alinitumia ujumbe wa sauti jana usiku kupitia simu janja.

Breakdown:

a- = she
-li- = past
-ni- = me
-tumia = sent to
→ She sent me a voice message last night via smartphone.