Learn Hardcore Swahili: Mwalimu wetu ni mtulivu darasani.

Mwalimu wetu ni mtulivu → Our teacher is calm
Ni does not change for person or number (no different forms like am/is/are).
In the negative, ni usually becomes si:
- Mwalimu wetu si mtulivu darasani → Our teacher is not calm in class.

Why is it mwalimu wetu and not mwalimu yetu for “our teacher”?

In Swahili, possessives must agree with the noun class of the noun they modify.

Mwalimu is in noun class 1 (the m-/wa- class for people).
The possessive for “our” in class 1 is wetu, not yetu.

Compare:

mwalimu wetu → our teacher (class 1 → wetu)
walimu wetu → our teachers (class 2 plural → still wetu)
kitabu chetu → our book (class 7 → chetu, not wetu)
shule yetu → our school (class 9 → yetu)

So wetu is specifically the form that matches m-/wa- nouns like mwalimu.

Where does the possessive wetu go in relation to mwalimu?

In Swahili, possessive adjectives normally come after the noun:

mwalimu wetu → our teacher
rafiki wangu → my friend
kitabu chako → your book

If you say Mwalimu ni wetu, that changes the meaning to “The teacher is ours” (focusing on who owns the teacher), not just “our teacher” as a simple noun phrase. So mwalimu wetu is the normal way to say “our teacher”.

What exactly does mtulivu mean, and is it an adjective?

Yes, mtulivu functions as an adjective here. It describes a person who is:

calm
quiet (in behavior, not noisy)
composed, not easily agitated

So Mwalimu wetu ni mtulivu is more like “Our teacher is calm / a calm person” than “Our teacher is silent.”

For plural:

mtu mtulivu → a calm person
watu watulivu → calm people
mwalimu mtulivu → a calm teacher
walimu watulivu → calm teachers

Notice the change m- → wa- for singular/plural agreement in this adjective type.

How does mtulivu agree with mwalimu?

Mtulivu agrees with mwalimu in noun class and number:

mwalimu mtulivu → calm teacher (singular, class 1 → m-)
walimu watulivu → calm teachers (plural, class 2 → wa-)

So in the sentence:

Mwalimu wetu ni mtulivu darasani.

the subject mwalimu is singular, so the describing word stays mtulivu, not watulivu.

What is darasani, and how is it formed?

Darasani means “in the classroom” / “in class”.

It is formed from:

darasa → classroom, class
-ni → locative suffix, often meaning “in/at/on”

So:

darasa → classroom
darasani → in the classroom / in class

This -ni locative is very common:

nyumba → house → nyumbani → at home
shule → school → shuleni → at school
soko → market → sokoni → at the market

Could I say katika darasa instead of darasani? Is there a difference?

Yes, you can say:

Mwalimu wetu ni mtulivu katika darasa.

This is grammatically correct and means essentially the same thing: “Our teacher is calm in the classroom.”

Differences:

darasani is very natural and idiomatic; it’s the default way to say “in class”.
katika darasa is a bit more explicit/formal, literally “in the classroom”.

In everyday speech, darasani is more commonly used.

Can the word order change, or must it be Mwalimu wetu ni mtulivu darasani?

The given order is the most neutral:

[Subject] [copula] [description] [place]
Mwalimu wetu ni mtulivu darasani.

You can move the place expression for emphasis:

Darasani, mwalimu wetu ni mtulivu.
In class, our teacher is calm (as opposed to other situations).

But you normally keep the subject first and don’t break up the core structure in unnatural ways like:

✗ Mwalimu wetu darasani ni mtulivu (possible in some spoken contexts, but less standard)
✗ Mtulivu ni mwalimu wetu darasani (strongly marked; sounds like a special focus or poetic style)

For a learner, it’s best to stick with:

Mwalimu wetu ni mtulivu darasani.

Why is there no word for “the” or “a” before mwalimu?

Swahili does not use articles like “a/an/the”.

mwalimu can mean “a teacher” or “the teacher”, depending on context.
mwalimu wetu clearly means “our teacher”, and that already specifies which teacher, so no article is needed.

English must choose a/the, but Swahili leaves that to context, not to a specific word.

How would I make the sentence plural: “Our teachers are calm in class”?

Change the noun and the agreeing adjective to the plural:

Walimu wetu ni watulivu darasani.

Changes:

mwalimu → walimu (teacher → teachers)
mtulivu → watulivu (calm [singular] → calm [plural])
wetu stays the same, because it already matches the wa‑ class for people in both singular and plural possessives.

So singular vs plural:

Mwalimu wetu ni mtulivu darasani.
Walimu wetu ni watulivu darasani.

How would I say “Our teacher is not calm in class” using this structure?

Use the negative form of ni, which is si in the present tense:

Mwalimu wetu si mtulivu darasani.
→ Our teacher is not calm in class.

Structure:

Mwalimu wetu (our teacher)
si (is not)
mtulivu (calm)
darasani (in class)