Learn Hardcore Swahili: Chumba cha kulala ni kimya usiku.

Swahili often names places by saying “place of doing X”, so chumba cha kulala is naturally understood as bedroom – the room used for sleeping.

What is the role of cha in chumba cha kulala?

cha is a possessive/connecting word that links two nouns (or a noun and a verb-noun) in a “of / for” relationship.

Here it connects:

chumba (room)
with kulala (sleeping)

So chumba cha kulala = room of/for sleeping.
In grammar terms, cha is the possessive concord that agrees with the noun class of chumba.

Why is it cha and not ya, la, or another form?

Swahili has noun classes, and many words change form to agree with the class of the noun they refer to.

chumba is in noun class 7 (singular, often with chi-/ki-/ch-).
The class‑7 “of” form is cha.

Some other examples:

gari la mtoto – the child’s car (class 5: gari, so la)
kitabu cha Kiswahili – a Swahili book (class 7: kitabu, so cha)
meza ya mwalimu – the teacher’s table (class 9: meza, so ya)

So cha is chosen because it agrees with chumba.

What exactly is kulala here – a verb, a noun, or an infinitive?

kulala is the infinitive form of the verb lala (to sleep).

In Swahili, the infinitive ku- + verb (like kulala) can act like a noun, meaning “sleeping” or “to sleep” as a concept. That’s why it can be used after cha:

chumba cha kulala – room for sleeping
nafasi ya kuandika – space to write / writing space

So here kulala is a verb used as a noun (a verbal noun).

Could you say just chumba instead of chumba cha kulala and still be correct?

Yes and no.

chumba alone simply means room.
chumba cha kulala specifies bedroom.

If the context is very clear (for example, you are standing in a house and pointing), chumba might be understood as the bedroom, but grammatically it is just room. To be precise, you normally say chumba cha kulala for bedroom.

What does ni do in this sentence? Is it the verb to be?

Yes. ni is the copula, functioning like the English is / am / are.

In the sentence:

Chumba cha kulala = subject (The bedroom)
ni = is
kimya = quiet
usiku = at night

So Chumba cha kulala ni kimya usiku = The bedroom is quiet at night.

In ni kimya, is kimya an adjective or a noun? And why does it start with ki-?

kimya can be both a noun (“silence”) and an adjective-like word meaning “quiet, silent.” In this sentence it works like an adjective describing chumba.

The ki- at the beginning is related to the class 7 pattern (the same class as chumba). Many descriptive words that start with ki- are associated with this class and are used predicatively:

Chumba ni kikubwa – The room is big.
Chumba ni kimya – The room is quiet.

So kimya agrees in form with the kind of word typically used with ki-/ch- nouns like chumba.

How would you say “The bedrooms are quiet at night” in Swahili?

You need to make both the noun and the possessive plural:

Singular: chumba cha kulala – bedroom
Plural: vyumba vya kulala – bedrooms

The sentence:

Vyumba vya kulala ni kimya usiku.
= The bedrooms are quiet at night.

Notes:

chumba → vyumba (class 7 → class 8 plural)
cha → vya (possessive agreeing with the plural vyumba)
ni kimya stays the same; many predicate words do not change for plural in this type of structure.

Why is there no word for “at” before usiku? Can you say kwa usiku?

Time words like leo (today), kesho (tomorrow), usiku (night) often don’t need a preposition in Swahili. You simply put the time expression in the sentence:

Chumba cha kulala ni kimya usiku.
= literally Bedroom is quiet night → understood as at night.

Using kwa usiku in this meaning is not natural. You normally just say usiku without a preposition for at night.

Can usiku go in a different place in the sentence, like at the beginning?

Yes. Time expressions are quite flexible. All of these are possible and natural:

Chumba cha kulala ni kimya usiku.
Usiku chumba cha kulala ni kimya.

Putting usiku at the beginning just emphasizes “at night” more, but the meaning is the same. The most neutral, textbook-like word order is the original one with usiku at the end.

How do you say “The bedroom is not quiet at night” in Swahili?

You make ni negative:

Chumba cha kulala si kimya usiku.
= The bedroom is not quiet at night.

Here si is the negative form that corresponds to ni in this kind of equational sentence.

Are there other common words for “quiet” besides kimya, and do they change with noun classes?

Yes. Two common ones are:

kimya – quiet, silent (also “silence”)
tulivu – calm, peaceful, tranquil

In many simple “X is Y” sentences, these words appear in one fixed form and don’t visibly change for singular/plural:

Chumba cha kulala ni kimya. – The bedroom is quiet.
Vyumba vya kulala ni kimya. – The bedrooms are quiet.
Bahari ni tulivu. – The sea is calm.

Some adjectives clearly change with noun class when they are used attributively (directly before/after a noun), but in the structure X ni [description], the describing word often keeps one form, like kimya, tulivu, safi, chafu, etc.