Umaskini ni tatizo kubwa.

Yes—here, ni works like is in English.

It links umaskini and tatizo kubwa, so the sentence is an equational sentence: one thing is being identified as another thing.

A useful point for learners: ni does not change for singular, plural, or person.

• Umaskini ni tatizo kubwa. = Poverty is a big problem.
• Watoto ni tatizo kubwa. = Children are a big problem.
• Mimi ni mwalimu. = I am a teacher.

So in this kind of sentence, ni is very stable.

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

So tatizo kubwa can mean:

• a big problem
• the big problem

The exact meaning depends on context.

That is very normal in Swahili. Learners coming from English often expect a separate word for a or the, but Swahili generally just leaves that unstated.

Because that is the normal word order in Swahili: noun + adjective.

So:

• tatizo kubwa = big problem
• mtoto mdogo = small child
• nyumba nzuri = nice house

This is the opposite of normal English adjective order, so it is something English speakers have to get used to.

Because kubwa has to agree with tatizo, not with umaskini.

In this sentence, kubwa describes tatizo, so its form depends on the noun class of tatizo. Tatizo is a class 5 noun, and with class 5, the adjective form is kubwa.

Compare:

• mtoto mkubwa = big child
  (mtoto is class 1, so you get mkubwa)
• tatizo kubwa = big problem
  (tatizo is class 5, so you get kubwa)

So the form of the adjective changes according to the noun it modifies.

There are two important nouns here:

• umaskini — usually treated as class 14, a class often used for abstract ideas
• tatizo — class 5 singular
  Its plural is matatizo in class 6

This matters because noun class affects agreement, especially with adjectives and some other modifiers.

That is why:

• tatizo kubwa = big problem
• matatizo makubwa = big problems

So if you change tatizo to plural, kubwa also changes to makubwa.

Yes. They are closely related.

• maskini = poor, or a poor person
• umaskini = poverty

The prefix u- often forms an abstract noun, especially for qualities or states. So a learner can think of this as something like:

• maskini → poor
• umaskini → poverty / poorness

This is a very useful pattern in Swahili.

In standard Swahili, no—you should keep ni here.

Because this sentence is linking one noun phrase to another noun phrase, ni is the normal and correct connector:

• Umaskini ni tatizo kubwa.

Without ni, the sentence sounds incomplete or ungrammatical in standard usage.

So for a sentence of the form X is Y, ni is usually essential.

You would usually use si:

• Umaskini si tatizo kubwa. = Poverty is not a big problem.

Learners also sometimes hear sio, but si is the basic negative form to know for this kind of sentence.

So the contrast is:

• ni = is / are
• si = is not / are not

A simple pronunciation guide is:

• umaskini → u-ma-SKI-ni
• ni → nee
• tatizo → ta-TI-zo
• kubwa → KU-bwa

A few helpful pronunciation notes:

• Swahili stress usually falls on the second-to-last syllable
• bw in kubwa is said together, roughly like bwa
• Swahili vowels are usually pure and steady:
  • a as in father
  • i as in machine
  • u as in rule
  • o as in more without a glide

So the whole sentence is roughly:

u-ma-SKI-ni ni ta-TI-zo KU-bwa

Yes, but the emphasis changes.

The original sentence:

• Umaskini ni tatizo kubwa.

puts umaskini first as the topic.

If you say:

• Tatizo kubwa ni umaskini.

that means something more like:

• The big problem is poverty
• A big problem is poverty

So both are possible, but they do not sound identical in emphasis. The original version is the most straightforward way to say Poverty is a big problem.

Yes. A very common alternative is shida.

For example:

• Umaskini ni shida kubwa.

This also means Poverty is a big problem, though shida can feel a bit broader, like difficulty, trouble, or hardship, depending on context.

So:

• tatizo = problem
• shida = problem / difficulty / trouble

Both are useful, but tatizo is a very direct match for English problem.