Umaarufu umeongezeka.

Umaarufu is an abstract noun built from maarufu, which means famous / well-known.
Adding u- often creates a noun for a quality or state, so umaarufu means fame / popularity / renown.

So you can think of it roughly like:

• maarufu = famous
• umaarufu = fame / popularity

Because the word is formed from u- + maarufu. Both vowels stay in the spelling:

• u-
  • maarufu → umaarufu

Swahili often writes both vowels when morphemes come together, so this spelling is normal.

That u- is the subject agreement prefix. In Swahili, the verb must agree with the noun that is doing the action or being described.

Here, the subject is umaarufu, so the verb also uses u-:

• u- = subject agreement for this noun type
• -me- = perfect marker
• -ongezeka = increase / become greater

So:

• umeongezeka = u-me-ongezeka

-me- is a very common Swahili tense/aspect marker. It usually gives a perfect meaning, often translated as:

• has increased
• has gone up
• has grown

So umaarufu umeongezeka means that the increase has already happened, and the result is relevant now.

No. Swahili usually does not use a separate helper word like English has here. Instead, that meaning is built into the verb itself.

In umeongezeka:

• u- = subject
• -me- = has
• -ongezeka = increased / become greater

So one Swahili verb can correspond to several English words.

-ongezeka means to increase, to become more, to go up, or to grow in an intransitive sense.

That means the thing itself is changing:

• Umaarufu umeongezeka = popularity has increased
• Bei imeongezeka = the price has increased

It describes something becoming greater on its own, not something actively increasing something else.

This is an important distinction:

• -ongezeka = increase / become greater

  • intransitive
  • the subject itself goes up

• -ongeza = increase something / add

  • transitive
  • the subject causes something else to go up

Examples:

• Umaarufu umeongezeka. = Popularity has increased.
• Wameongeza bei. = They have increased the price.
• Niongezee maji. = Add more water for me.

So in your sentence, -ongezeka is correct because popularity itself is what has gone up.

Yes, but the meaning changes.

• Umaarufu umeongezeka = popularity has increased
• Umaarufu unaongezeka = popularity is increasing / increases

So:

• -me- often points to a completed change with a current result
• -na- often shows an ongoing or more general present action

A helpful breakdown is:

• u-maa-ru-fu
• u-me-o-nge-ze-ka

The usual stress in Swahili falls on the second-to-last syllable of each word:

• u-maa-RU-fu
• u-me-o-nge-ZE-ka

A few pronunciation notes:

• every vowel is pronounced clearly
• ng in nge is pronounced like the ng in finger, not like nj
• e and o are pure vowels, not English-style diphthongs

Normally, umaarufu is an abstract noun, so it usually does not have a regular plural in everyday use.

It works a lot like English popularity or fame: these are qualities or states, not countable objects.

So you normally talk about:

• umaarufu mkubwa = great popularity
• umaarufu umeongezeka = popularity has increased

rather than a plural form.

Swahili does not have articles like English the or a/an. Context tells you whether something is definite or general.

So Umaarufu umeongezeka can naturally mean:

• Popularity has increased
• or, depending on context, The popularity has increased

Swahili simply does not need a separate article word here.