Mkutano ukikamilika, tutarudi nyumbani.

ukikamilika can be broken down like this:

• u- = subject marker agreeing with mkutano
• -ki- = a marker often meaning if/when
• kamilika = be completed, come to an end

So mkutano ukikamilika literally means something like the meeting when it is completed or more naturally when the meeting is over / once the meeting ends.

Because mkutano belongs to a noun class that takes the subject marker u- in the singular.

In Swahili, verbs must agree with the noun they refer to. So:

• mkutano = singular
• its agreement marker here = u-

That is why you get u-kikamilika.

If the noun were plural, the agreement would change. For example:

• mikutano = meetings
• the subject marker would be i-

So noun class agreement is the reason for u-.

It can mean either, depending on context. In this sentence, when/once is the most natural meaning.

Why? Because the meeting is expected to finish, so this is not really a doubtful condition. It is more a time relationship:

• Mkutano ukikamilika, tutarudi nyumbani.
• When the meeting is over, we will return home.

So although -ki- is often taught as if, it very often also works as when in sentences like this.

Because kamilika is intransitive: it means to be completed or to come to completion.

That fits mkutano well:

• Mkutano ukikamilika = when the meeting is completed / ends

By contrast, kumaliza usually means to finish something and is transitive, so it normally needs a doer and often an object:

• Nitamaliza kazi = I will finish the work

So kamilika focuses on the meeting reaching its end, not on someone actively finishing it.

tutarudi breaks down as:

• tu- = we
• -ta- = future tense marker
• rudi = return / go back

So tutarudi means we will return or we will go back.

Because the subject is already included in the verb.

In Swahili, verbs usually contain the subject marker, so a separate pronoun is often unnecessary.

• tu-ta-rudi already means we will return

You could add sisi for emphasis:

• Sisi tutarudi nyumbani = We will return home

But in a normal sentence, tutarudi by itself is enough.

Because nyumbani is a locative form. It comes from nyumba (house/home) plus -ni, which gives a location-related meaning.

So nyumbani can mean:

• at home
• home
• sometimes to the house/home

The exact meaning depends on the verb and context. After a motion verb like kurudi (to return), it naturally means home or back home:

• tutarudi nyumbani = we will return home

Yes. The time clause can come first or second.

For example:

• Mkutano ukikamilika, tutarudi nyumbani.
• Tutarudi nyumbani mkutano ukikamilika.

Both are understandable. Putting mkutano ukikamilika first gives it a strong when/once emphasis, similar to English When the meeting is over, ...

Yes, that is possible, and it makes the future-time meaning more explicit.

Compare:

• ukikamilika = when/if it gets completed, once it ends
• utakapokamilika = when it will have been completed / when it is completed in a clearly future sense

So:

• Mkutano ukikamilika, tutarudi nyumbani.
• Mkutano utakapokamilika, tutarudi nyumbani.

Both can work. The version with -ki- is shorter and very natural. The version with -takapo- sounds more explicitly tied to a future point in time.

It is closest to when the meeting is finished or once the meeting is finished.

In real usage, that often implies the same result as English after the meeting is finished, but grammatically the Swahili clause is presenting the meeting’s completion as the time point at which the next action happens.

So a natural interpretation is:

• Once the meeting is over, we’ll go home.

That is probably the smoothest English sense.