Yeye atakaa kimya darasani wakati wa mtihani.

Because yeye adds emphasis or clarity.

In atakaa, the a- already means he/she, so the sentence would still be grammatical without yeye:

Atakaa kimya darasani wakati wa mtihani.

Adding yeye can make it feel more like:

• He/She will stay quiet...
• As for him/her, he/she will stay quiet...

So yeye is often optional unless you want emphasis, contrast, or extra clarity.

atakaa can be broken down like this:

• a- = he/she
• -ta- = future tense marker, will
• kaa = stay, remain, sit

So atakaa means he/she will stay/remain/sit.

The verb kaa can mean several related things, including:

• sit
• stay
• remain
• live (in some contexts)

In this sentence, because of kimya, the most natural meaning is:

• will remain quiet
• will stay quiet
• will keep quiet

It could also suggest sit quietly, depending on context, but remain quiet is usually the best interpretation.

kimya means silence or quiet.

In the expression kaa kimya, it means:

• be quiet
• keep quiet
• remain silent

So kimya is not acting like a normal English-style adjective here. It is part of a very common expression. You can think of kaa kimya as a set phrase meaning stay quiet.

darasani means in the classroom or in class.

It comes from:

• darasa = classroom / class
• -ni = a locative ending meaning something like in, at, on

So:

• darasa = classroom
• darasani = in the classroom

Swahili often uses this -ni ending instead of a separate preposition like in.

Literally, it means the time of the exam.

More naturally in English, it means:

• during the exam
• at exam time

This pattern is very common:

• wakati wa chakula = during mealtime
• wakati wa likizo = during the vacation/holiday

So wakati wa mtihani is a normal way to say during the exam.

wa is a connector often translated as of.

So:

• wakati wa mtihani = time of the exam

In natural English, that becomes during the exam.

This kind of connector is very common in Swahili, especially in phrases showing possession or relationship.

It can mean either he or she.

Swahili does not normally mark gender in third-person singular pronouns the way English does. So:

• yeye = he / she
• a- in the verb = he / she

You understand the gender from context, if it matters at all.

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

So mtihani can mean:

• an exam
• the exam

and darasani can mean:

• in a classroom
• in the classroom

The exact meaning depends on context. English requires articles, but Swahili usually does not.

Yes. A very natural version is:

Atakaa kimya darasani wakati wa mtihani.

That still means He/She will remain quiet in the classroom during the exam.

Because the verb already shows the subject, yeye is not necessary unless you want emphasis.

Yes, somewhat.

The original sentence is natural:

Yeye atakaa kimya darasani wakati wa mtihani.

But you can move some parts for emphasis, for example:

Wakati wa mtihani, yeye atakaa kimya darasani.

This gives more focus to during the exam.

Swahili allows some flexibility, especially with time and place phrases, although subject + verb remains the main core of the sentence.

The two vowels are both pronounced. Swahili spelling is usually very regular.

So atakaa is pronounced roughly as:

a-ta-ka-a

The aa is not silent, and you should not reduce it to one short vowel. Each vowel is heard clearly. This is a common feature of Swahili pronunciation.