Ni baada ya kuunganisha kebo ya modemu ndipo mtandao ulirudi.

It adds focus and emphasis.

In Ni baada ya kuunganisha kebo ya modemu ndipo mtandao ulirudi, the speaker is highlighting the time phrase baada ya kuunganisha kebo ya modemu.

A very literal sense is:

It was after connecting the modem cable that the internet returned.

In natural English, this often feels like:

Only after the modem cable was connected did the internet come back.

So ni ... ndipo is a very common way to say it is/was X that/when Y.

Because baada ya means after, and in Swahili it can be followed by:

• a noun, or
• an infinitive/verbal noun

Here, kuunganisha is the infinitive to connect, but after baada ya it works like connecting in English.

So:

• baada ya kuunganisha = after connecting

This is a very normal and common structure in Swahili.

Kuunganisha is the infinitive form of the verb -unganisha, meaning to connect / to join.

It breaks down like this:

• ku- = infinitive marker, like to in to connect
• -unganisha = the verb stem

So:

• kuunganisha = to connect
• in this sentence, because of baada ya, it has the sense connecting

This is an active form. It means someone connected the cable.

This is the normal Swahili way to show possession or association:

noun + possessive linker + noun

So:

• kebo = cable
• ya = of
• modemu = modem

Together:

• kebo ya modemu = modem cable or literally cable of the modem

The linker is ya because it agrees with kebo, which belongs to noun class 9.

Here, ndipo means something like:

• that is when
• then
• that was when

In this sentence, it connects the emphasized first part to the main event:

• Ni baada ya kuunganisha kebo ya modemu ndipo mtandao ulirudi
• It was after connecting the modem cable that the internet returned

So in this pattern, ndipo is not just a simple then. It helps create the focused structure it was then that...

Because the subject is mtandao, and mtandao belongs to noun class 3 in the singular.

The verb agrees with that noun class:

• u- = subject marker for class 3 singular
• -li- = past tense
• -rudi = return / come back

So:

• u-li-rudi = it returned / it came back

That is why you get:

• mtandao ulirudi = the network/internet returned

It can mean both, depending on context.

Literally, mtandao often means network. But in everyday use it can also mean:

• the internet
• internet connection
• service/network connection

In this sentence, the context clearly points to the internet/network connection coming back.

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

So words like:

• kebo
• modemu
• mtandao

do not need separate words for the.

Whether English uses a or the is understood from context. That is why kebo ya modemu can mean:

• a modem cable
• the modem cable

and mtandao can mean:

• a network
• the network / the internet

depending on the situation.

It is normal, but it is more emphatic than the most neutral version.

This sentence puts the time phrase first and uses ni ... ndipo to emphasize it.

A more neutral version would be:

• Mtandao ulirudi baada ya kuunganisha kebo ya modemu.
• Baada ya kuunganisha kebo ya modemu, mtandao ulirudi.

Those mean basically the same thing, but Ni ... ndipo ... makes the timing stand out more strongly.

No. The sentence does not explicitly say who did the connecting.

Kuunganisha here just gives the action connecting, without naming the person.

So the subject of that action is understood from context. It could mean:

• after I connected it
• after we connected it
• after someone connected it

If you want to state the person clearly, you can add it, for example:

• baada ya mimi kuunganisha kebo ya modemu = after I connected the modem cable
• baada ya fundi kuunganisha kebo ya modemu = after the technician connected the modem cable

Yes. If you want to focus on the cable being connected, rather than on someone connecting it, you could use the passive:

• kuunganishwa = to be connected

For example:

• Baada ya kebo ya modemu kuunganishwa, mtandao ulirudi.

That means:

After the modem cable was connected, the internet returned.

So:

• kuunganisha = to connect (active)
• kuunganishwa = to be connected (passive)

The original sentence uses the active-style infinitive, which is very natural.