Learn Hardcore Swahili: Usiku tunafunga pazia zito ili nyumba yetu yenye madirisha makubwa iwe na faragha. - At night we close the heavy curtain so that our house with big windows has privacy.

Usiku literally means “night”, but in context it works like “at night”.
You don’t need to say kwa usiku or katika usiku. That would sound odd.

Both of these are correct and mean the same thing:

Usiku tunafunga pazia zito… – At night we close the heavy curtains…
Tunafunga pazia zito usiku… – We close the heavy curtains at night…

So Usiku at the front just sets the time frame: At night…

What exactly does tunafunga mean, and how is it built?

Tunafunga comes from the verb funga (to close, to shut, to fasten, to tie, to fast).

It has three parts:

tu- = we (subject prefix, 1st person plural)
-na- = present tense / habitual marker
-funga = close

So:

tunafunga = we close, we are closing, or we usually close (present / habitual).

In this sentence, it’s a habitual action:

Usiku tunafunga pazia zito…
At night we (usually) close the heavy curtains…

Why is it pazia zito and not mapazia or something like pazia nzito?

Pazia belongs to the JI/MA noun class (class 5/6):

Singular: pazia (a curtain)
Plural: mapazia (curtains)

Here, pazia is singular, but Swahili often uses the singular to refer to the thing in general or as a set (“the curtain(s)” as a unit on a window).

The adjective -zito means heavy. In the JI/MA class:

Singular: pazia zito – a heavy curtain
Plural: mapazia mazito – heavy curtains

You don’t say pazia nzito here. -nzito is the M-/MI class form (for words like mti mzito / miti mizito – heavy tree(s)), not for pazia.

So pazia zito is grammatically correct: a (or the) heavy curtain.

What does ili mean here, and how is it different from kwa sababu or hili?

In this sentence, ili introduces a purpose clause and means:

“so that” / “in order that”

So:

…tunafunga pazia zito ili nyumba yetu … iwe na faragha
= …we close the heavy curtains so that our house … may have privacy.

Differences:

ili = so that, in order that (purpose)
kwa sababu = because (reason/cause)
hili = this (thing) (demonstrative adjective/pronoun), not related to ili here

Example contrast:

Tunafunga pazia zito kwa sababu kuna jua.
We close the heavy curtains because there is sun. (reason)
Tunafunga pazia zito ili tusipate jua.
We close the heavy curtains so that we don’t get sun. (purpose)

Why do we say nyumba yetu and not *nyumba wetu? How does yetu work?

Nyumba is in noun class 9/10, and possessive adjectives must agree with the noun class.

The base form -etu means “our”, but it changes its prefix according to the noun class. For class 9/10, the agreement prefix is y-:

nyumba yetu – our house
nyumba yangu – my house
nyumba yako – your house (singular)

If it were a class 1 noun like mtoto:

mtoto wetu – our child (same -etu, but different prefix/concord pattern)

So nyumba yetu is the correct agreement pattern for a class 9 noun.

What does yenye mean in nyumba yetu yenye madirisha makubwa?

Yenye comes from -enye, which means roughly “which has” or “with”.

So:

nyumba yetu yenye madirisha makubwa
= our house *which has big windows
= our house **with big windows*

You can often paraphrase yenye with ambayo ina:

nyumba yetu ambayo ina madirisha makubwa – literally our house which has big windows

Using -enye is a compact way to say something “with X”:

mtu mwenye uwezo – a person with ability
kitabu chenye picha nyingi – a book with many pictures

Why is it madirisha makubwa and not dirisha kubwa or madirisha kubwa?

The noun dirisha (window) is also in the JI/MA class:

Singular: dirisha – a window
Plural: madirisha – windows

The adjective -kubwa (big) must agree with the noun’s class and number.

For JI/MA:

Singular: dirisha kubwa – a big window
Plural: madirisha makubwa – big windows

So:

madirisha makubwa = big windows (plural)
If it were just one window: dirisha kubwa = a big window

Why is yenye used instead of a relative pronoun like ambayo in this phrase?

Both yenye and ambayo can introduce a relative idea about “the house”, but they’re used differently:

yenye → “which has / with”
ambayo → “which / that” (more general relative pronoun)

Compare:

nyumba yetu yenye madirisha makubwa
our house with big windows (literally: our house which has big windows)
nyumba yetu ambayo ina madirisha makubwa
our house which has big windows (more explicit, a full relative clause)

-enye is usually followed directly by a noun:

mji wenye watu wengi – a town with many people
chumba chenye mwanga mzuri – a room with good light

Ambayo tends to start a full clause with a verb (ina, iko, etc.). Using yenye makes the phrase more compact and descriptive.

What is iwe and why do we use that form instead of inakuwa or iko?

Iwe is the subjunctive form of the verb kuwa (to be), in the present tense, class 9 subject (nyumba):

kuwa – to be
iwe – (that it) be / may be

We use the subjunctive after ili to express a desired or intended result:

ili nyumba yetu … iwe na faragha
= so that our house may have privacy / so that our house will have privacy

If you said:

nyumba yetu ina faragha – our house has privacy (simple present statement)
nyumba yetu inakuwa na faragha – our house is becoming / tends to have privacy (progressive/habit)
nyumba yetu iko na faragha – regional/colloquial for “has privacy” in some varieties

But after ili, the natural choice is the subjunctive iwe, because it’s about the purpose or intended state, not just a plain fact.

What does na mean in iwe na faragha? Is it the same na as “and”?

Yes, it’s the same word na, but here it plays the role of “with / having”.

In Swahili, the structure kuwa na X means “to have X”:

kuwa na pesa – to have money
kuwa na marafiki – to have friends
kuwa na faragha – to have privacy

So:

nyumba yetu iwe na faragha
= our house may have privacy
(literally: our house may be with privacy)

The same na is also used for “and”, but in kuwa na it’s best thought of as “with”.

What does faragha mean exactly, and is it used only for “privacy”?

Faragha generally means:

privacy, seclusion, being out of public view, sometimes intimacy.

In this sentence:

iwe na faragha = may have privacy
(i.e., people outside can’t see in through the big windows).

Other examples:

Ninahitaji faragha kidogo. – I need a bit of privacy.
Walizungumza kwa faragha. – They spoke in private.

So the meaning is quite close to English privacy / in private, and can also carry a sense of being hidden/away from others’ eyes.

Could this sentence be phrased as Usiku tunafunga pazia zito ili tupate faragha? What’s the difference?

Yes, you could say:

Usiku tunafunga pazia zito ili tupate faragha.

That means:

At night we close the heavy curtains so that we may get/obtain privacy.

Difference in focus:

Original sentence:
- …ili nyumba yetu … iwe na faragha.
  Focuses on the house: so that our house may have privacy.
Alternative sentence:
- …ili tupate faragha.
  Focuses on us: so that we may get privacy.

Both are grammatically correct. The original highlights the state of the house (a house with big windows that needs to “have privacy”), while the alternative emphasizes our benefit.