Juma aliandika alama ya mshangao badala ya koma, kwa hiyo mwalimu akamwonyesha kosa hilo.

Aliandika can be split as:

• a- = subject marker for he/she
• -li- = past tense
• -andika = write

So aliandika means he/she wrote. Since Juma is already named, the full phrase Juma aliandika means Juma wrote.

Swahili often links two nouns with a connector meaning of. That connector changes form depending on the noun class of the first noun.

Here:

• alama = mark/sign
• ya = the of connector that matches alama
• mshangao = exclamation/surprise

So alama ya mshangao literally means sign/mark of exclamation, which is the normal Swahili way to say exclamation mark.

Badala ya is a fixed expression meaning instead of or in place of.

So:

• badala ya koma = instead of a comma

It works much like a prepositional phrase in English.

Swahili does not have articles that work like English a, an, the.

So a noun like mwalimu can mean:

• a teacher
• the teacher

and koma can mean:

• a comma
• the comma
• just comma, depending on context

The exact meaning is usually understood from the situation.

Kwa hiyo means so, therefore, for that reason, or as a result.

Literally, it is close to because of that or by that. In this sentence, it connects the result in the second clause to what happened in the first clause.

The -ka- in akamwonyesha is a consecutive or narrative marker. It often shows the next event in a sequence, something like:

• and then
• so then
• whereupon

So:

• a-ka-mw-onyesha = he/she then showed him/her

Using alimwonyesha would also mean he/she showed him/her, but akamwonyesha makes the sequence more vivid and connected: first Juma made the punctuation mistake, and then/as a result the teacher pointed it out.

mw- is an object marker meaning him/her for a singular human object.

So akamwonyesha includes the idea of showed him or showed her. In this sentence, it refers back to Juma, so the meaning is showed him.

This is very common in Swahili: object pronouns are often built directly into the verb.

Because they are doing different jobs.

• mw- = the person receiving the action: him
• kosa hilo = the thing being shown: that mistake

So:

• akamwonyesha kosa hilo = he showed him that mistake

A natural English translation is often the teacher pointed out that mistake to him.

Its basic meaning is show.

But in context, show someone a mistake often translates more naturally as point out a mistake. So both ideas are correct:

• literal: showed him that mistake
• natural English: pointed out that mistake to him

You may also see the shorter spelling -onesha, which is very common in everyday Swahili.

Because kosa belongs to noun class 5, and demonstratives must agree with the noun’s class.

For kosa, the correct forms are:

• kosa hili = this mistake
• kosa hilo = that mistake

So hilo is the correct form here. Hiyo would not agree with kosa.

It refers back to the mistake already mentioned: writing an exclamation mark instead of a comma.

So kosa hilo means that mistake, specifically the mistake just mentioned. In English, depending on style, you might translate it as:

• that mistake
• the mistake
• that error

Here it is singular: teacher.

The plural is walimu = teachers.

The verb also confirms this, because a- in akamwonyesha is a singular subject marker. So mwalimu akamwonyesha means the teacher then showed him.