Swali la Asha lilikuwa na alama ya kuuliza, lakini Juma akaweka alama ya mshangao kwa makosa.

Because swali belongs to noun class 5, and the linking word that means of must agree with that noun class.

So:

• swali = question
• la = of for class 5 nouns

That gives:

• Swali la Asha = Asha’s question / the question of Asha

The form ya is also a linker meaning of, but it is used with different noun classes. In this sentence, la is the correct agreement form for swali.

Lilikuwa means it was.

It breaks down like this:

• li- = subject marker for noun class 5, matching swali
• -li- = past tense
• kuwa = to be

So swali ... lilikuwa literally means the question ... it was.

English does not show noun class agreement this way, but Swahili does. Since swali is class 5, the verb must use the class 5 subject marker li-.

Here na means with / having.

So:

• lilikuwa na alama ya kuuliza = it had a question mark

Swahili often uses kuwa na for the idea of have:

• Ana kitabu = He/she has a book
• Swali lilikuwa na alama = The question had a mark

So instead of a separate verb like English have, Swahili commonly uses be with.

This is a noun phrase built from:

• alama = mark / sign / symbol
• ya = linking word meaning of, agreeing with alama
• kuuliza = to ask / asking

So literally it is something like mark of asking, which corresponds to question mark.

This is very normal in Swahili: a concept that is one word in English may be expressed as a descriptive phrase.

Because alama belongs to noun class 9, and the connector for that class is often ya.

So:

• alama ya kuuliza = question mark
• alama ya mshangao = exclamation mark

The ya does not come from kuuliza or mshangao. It agrees with alama, the noun being described.

Mshangao means surprise or exclamation.

So:

• alama ya mshangao literally = mark of exclamation/surprise
• natural English equivalent = exclamation mark

This is parallel to:

• alama ya kuuliza = question mark

Akaweka is a very common narrative form in Swahili.

It breaks down roughly as:

• a- = he/she
• -ka- = narrative/sequential marker
• weka = put/place

In a sentence like this, akaweka often means something like:

• and then he put
• but he put
• he went and put

It helps move the story forward.

If you said aliweka, that would simply mean he put in an ordinary past tense.
Using akaweka gives the sentence a more connected, story-like flow after the first clause.

Yes, a little in context.

• lakini = but
• akaweka = then he put / he went and put

Together, the sentence has the feeling:

• ..., but Juma then put ...

So lakini gives the contrast, while akaweka keeps the action moving forward. The combination is natural in storytelling or explanation.

Kwa makosa means by mistake or mistakenly.

Breakdown:

• kwa = by / in / through / in the manner of
• makosa = mistakes / errors

Literally, it is something like in error(s), but the natural English meaning is by mistake.

You can use it in many sentences:

• Nilichukua kitabu kwa makosa. = I took the book by mistake.
• Aliandika jina langu kwa makosa. = He/she wrote my name by mistake.

That is just how the expression works in normal Swahili. Makosa is the usual form in the fixed expression kwa makosa.

Even though English says by mistake with a singular noun, Swahili idiomatically uses makosa. So it is best learned as a set phrase:

• kwa makosa = by mistake

Yes. A more literal breakdown is:

• Swali la Asha = Asha’s question
• lilikuwa na = had / was with
• alama ya kuuliza = a question mark
• lakini = but
• Juma = Juma
• akaweka = then he put
• alama ya mshangao = an exclamation mark
• kwa makosa = by mistake

So a very literal version would be:

Asha’s question was with a question mark, but Juma then put an exclamation mark by mistake.

That is less natural in English, but it helps show how the Swahili is built.

No. Swali means question, not question mark.

The punctuation mark is:

• alama ya kuuliza = question mark

So the sentence is talking about Asha’s question, and then describing what punctuation mark it had.

Yes: Swahili agreement is doing a lot of work here.

Notice these parts:

• Swali la Asha: la agrees with swali
• swali ... lilikuwa: li- agrees with swali
• alama ya kuuliza: ya agrees with alama
• alama ya mshangao: ya again agrees with alama

For an English speaker, one of the biggest habits to build in Swahili is checking which noun the grammar is agreeing with. That often determines forms like la, ya, and li-.