Kama yai ni bovu, litatoa harufu mbaya.

Here kama means if and introduces a condition.

So:

• Kama yai ni bovu = If an egg is bad / rotten

Be aware that kama can also mean like or as in other sentences, but in this sentence it is clearly the conditional if.

Swahili normally does not use articles like English a, an, or the.

So yai can mean:

• an egg
• the egg
• sometimes just egg, depending on context

In this sentence, English naturally translates it as an egg or the egg, but Swahili leaves that unstated.

Because ni is the copula here, meaning is.

• yai ni bovu = the egg is bad / rotten

This is different from:

• yai bovu = a bad egg / rotten egg

So:

• yai ni bovu is a full statement
• yai bovu is a noun phrase

That distinction is very important in Swahili.

Ni links the subject and the description, like is in English.

Here it connects:

• yai = egg
• bovu = bad / rotten / spoiled

So yai ni bovu literally works like egg is bad.

Bovu is the correct form here because yai is a singular noun in noun class 5.

A very useful comparison is:

• yai bovu = bad egg
• mayai mabovu = bad eggs

So when the noun becomes plural:

• yai → mayai
• bovu → mabovu

This is part of Swahili noun-class agreement.

Swahili often puts the subject marker, tense marker, and verb stem into one word.

Litatoa can be broken down like this:

• li- = subject marker for yai (class 5 singular), meaning it
• -ta- = future tense, will
• -toa = give out, produce, emit

So litatoa means it will give out or it will produce.

Because the it is already built into the verb.

In litatoa, the part li- refers back to yai.

So Swahili does not need a separate subject pronoun the way English does. Instead of saying it will give out, Swahili can express that in one verb form:

• li-ta-toa

Not exactly. The basic meaning of toa is something like take out, give out, or produce.

In this sentence, litatoa harufu mbaya literally means:

• it will give out a bad smell
• it will emit a bad odor

So the idea of smelling bad comes from giving off a bad smell, not from a separate verb meaning to smell.

In Swahili, adjectives normally come after the noun.

So:

• harufu mbaya = bad smell
• literally smell bad

This is the normal word order:

• noun first
• adjective second

Mbaya means bad.

So:

• harufu mbaya = bad smell
• smell that is bad

It is the adjective describing harufu.

Yes. This is a very normal and natural pattern:

• Kama
  • condition
• then the result clause

So the structure is:

• Kama yai ni bovu = If an egg is bad
• litatoa harufu mbaya = it will give off a bad smell

Swahili does not need an extra word for then here, although one can sometimes be added in other contexts.

You would say:

Kama mayai ni mabovu, yatatoa harufu mbaya.

Changes:

• yai → mayai = egg → eggs
• bovu → mabovu = bad/rotten in the plural
• litatoa → yatatoa because the subject marker changes to match mayai

So the sentence means:

• If eggs are rotten, they will give off a bad smell.