Jumba ni kubwa.

• jumba is the noun, the thing being talked about
• ni is the linking word, like is
• kubwa is the adjective big

So the pattern is:

noun + ni + adjective

Here, ni works like the English verb to be in the present tense, especially is.

So in this sentence, it links jumba with kubwa:

• Jumba ni kubwa = the mansion/building is big

A useful thing to remember is that ni does not change the way English am / is / are do. It stays ni.

Because this sentence is making a statement about the noun.

• Jumba ni kubwa = the mansion/building is big
• Jumba kubwa = a big mansion/building

That is an important difference:

• jumba ni kubwa is a full sentence
• jumba kubwa is just a noun phrase

Swahili usually does not use articles like English the and a/an.

So jumba can mean:

• a mansion/building
• the mansion/building

The exact meaning depends on context.

Kubwa is the adjective stem meaning big, and with jumba this is the correct form.

Swahili adjectives often change to match the noun class, but the form you see depends on the noun class involved. With jumba in the singular, kubwa is correct.

You can see the agreement more clearly in the plural:

• jumba ni kubwa = the mansion/building is big
• majumba ni makubwa = the mansions/buildings are big

So in the plural, kubwa changes to makubwa.

Jumba is normally in the ji-/ma- noun class system:

• singular: jumba
• plural: majumba

This matters because adjectives and some other words often agree with the noun class.

That is why the plural is:

• majumba ni makubwa

not majumba ni kubwa

The plural is:

Majumba ni makubwa.

Changes:

• jumba → majumba
• kubwa → makubwa
• ni stays the same

Not usually.

The most common general word for house/home is nyumba.

Jumba often suggests something larger or more impressive, such as:

• a large house
• a mansion
• a big building
• sometimes even a palace, depending on context

So a learner should not assume jumba and nyumba are always interchangeable.

For a normal full sentence like this, you should keep ni.

• Jumba ni kubwa = the mansion/building is big

If you remove ni and say jumba kubwa, that usually sounds like a noun phrase meaning:

• big mansion/building

So for learners, it is safest to treat ni as necessary here.

You can say:

Jumba si kubwa.

This means the mansion/building is not big.

You may also hear siyo in some contexts, but si kubwa is a very useful basic pattern to know.

You can often just use question intonation:

Jumba ni kubwa?

You can also add je at the beginning:

Je, jumba ni kubwa?

Both mean Is the mansion/building big?

A simple guide is:

JUM-ba ni KU-bwa

Swahili usually stresses the second-to-last syllable of a word.

A few pronunciation notes:

• j sounds like the j in jam
• u is like oo in food, but shorter
• bw is pronounced together

So kubwa sounds roughly like KOOB-wa, with the stress on KU.