Learn Hardcore Swahili: Tunapojadili habari darasani, ni muhimu tusibishane. - When we discuss news in class, it is important that we do not argue.

tunajadili habari darasani
= “we are discussing the news in class” / “we discuss the news in class”
(just a simple statement about what we do.)
tunapojadili habari darasani
= “when(ever) we discuss the news in class” / “while we are discussing the news in class”
(this introduces a time/condition clause, not a plain statement.)

So adding -po- turns it into a clause that sets the context for another action:
“When we discuss news in class, it’s important that we don’t argue.”

Could we also say tukijadili habari darasani instead of tunapojadili habari darasani? What’s the difference?

Yes, you can say:

Tukijadili habari darasani, ni muhimu tusibishane.

The difference in nuance:

tunapojadili uses -na-…-po-, a relative “when/while” form; it sounds slightly more neutral / general, like “whenever we discuss” or “when we discuss.”
tukijadili uses -ki- (tu-ki-jadili), a conditional/temporal marker often translated as “when/if/while we discuss.” It can sound a bit more like “whenever / when / if it happens that we discuss.”

In everyday speech, the difference is subtle, and both are acceptable here.

Is -po in tunapojadili a “where” word or a “when” word?

The -po marker is fundamentally locative, often translated as “where.”
But when it’s attached to a verb like this, context allows it to express time:

mahali tunapojadili = “the place where we discuss”
tunapojadili habari darasani = “when/while we discuss news in class”

So in this sentence, -po is understood as “when/while”, even though structurally it’s the same locative relative marker. Context decides whether it feels like “where” or “when.”

What exactly does habari mean here? Isn’t habari also used as a greeting?

Yes, habari is used in greetings, but its basic meaning is “news, information, reports.”

In greetings (e.g. Habari?, Habari za asubuhi?), it’s like asking “What’s the news?” / “How are things?” and functions as “Hello / How are you?”
In this sentence, Tunapojadili habari darasani, habari clearly means “news, information (e.g. from the media, current events).”

So here the sense is: “When we discuss news in class…” not “When we discuss greetings in class.”

What does darasani literally mean, and how is it formed?

Darasani comes from darasa (“classroom; class”) plus the locative ending -ni:

darasa = class / classroom
darasa + -ni → darasani = “in the class / in class / in the classroom.”

So habari darasani means “news (that we’re talking about) in class” or “news during class.”
The -ni locative is very common: nyumba → nyumbani (“at home”), kanisa → kanisani (“in/at church”), etc.

How is tusibishane formed, and what does it literally mean?

Tusibishane breaks down like this:

tu- = we (subject prefix)
-si- = negative marker (for subjunctive/imperative)
bish- = root from -bisha, “to contradict, object, argue, dispute”
-an- = reciprocal marker, “each other / one another”
-e = subjunctive final vowel

So tu-si-bish-an-e literally means:
“let us not argue with each other / let us not contradict one another.”

Affirmative would be tubishane = “let’s argue (with each other).”

Why does the sentence use tusibishane and not something like hatubishani?

hatubishani = “we do not argue (with each other)” — a statement of fact in the present.
tusibishane = “that we should not argue / let’s not argue” — an instruction / recommendation, not just a fact.

After expressions like ni muhimu (“it is important”), Swahili normally uses the subjunctive:

ni muhimu tusibishane
= “it is important (that) we not argue.”

Using hatubishani here would sound like you are describing a fact:
“As we discuss news in class, it’s important we don’t argue (and, in fact, we don’t).”
The original sentence is giving a rule or guideline, so tusibishane is correct.

Why is there no word for “it” in ni muhimu tusibishane (“it is important that we don’t argue”)?

Swahili often omits an explicit “it” in such impersonal sentences. The structure is:

ni = is (copula)
muhimu = important
tusibishane = that we not argue

So ni muhimu tusibishane is literally:

“is important (that) we not argue.”

English needs a dummy subject “it” (“It is important that…”), but Swahili does not.
If you wanted, you could add kwamba:

Ni muhimu kwamba tusibishane.
= “It is important that we don’t argue.”

Both are correct; the version without kwamba is very natural and common.

Can we reverse the order of the clauses, like Ni muhimu tusibishane tunapojadili habari darasani?

You can put the “it is important” part first, but you normally still keep the “when we discuss…” clause clearly marked, e.g.:

Ni muhimu tusibishane tunapojadili habari darasani.

This is understandable, but feels a bit heavier and slightly less natural than:

Tunapojadili habari darasani, ni muhimu tusibishane.

Why? Because in Swahili (as in English) it’s very natural to put the time/condition clause first:

“When we discuss news in class, it’s important that we don’t argue.”

If you start with Ni muhimu…, many speakers would prefer:

Ni muhimu tusibishane tunapojadili habari darasani.
or
Ni muhimu, tunapojadili habari darasani, tusibishane.

The original order is the cleanest and most typical.

Does tunapojadili here refer to a specific time, or does it mean “whenever we discuss”?

Tunapojadili with -na-…-po- usually has a general / habitual feel:

Tunapojadili habari darasani…
≈ “Whenever we discuss news in class…”
or “When we discuss news in class (generally speaking)…”

It can also be used for a more specific ongoing situation (“while we are discussing…”), but in a rule-like sentence with ni muhimu tusibishane, the most natural reading is general / habitual:
“Whenever we discuss news in class, it is important that we don’t argue.”