Barua hii inapaswa kusomwa kwa sauti darasani.

Because barua belongs to noun class 9 in the singular, and words that agree with it must use class 9 agreement.

So in this sentence:

• barua = letter
• hii = this, agreeing with a class 9 singular noun
• i-na-paswa = it should / it is supposed to

The i- at the start of inapaswa is the subject marker for a class 9 singular noun.

A useful thing to remember is that barua has the same form in singular and plural:

• barua hii inapaswa... = this letter should...
• barua hizi zinapaswa... = these letters should...

So the agreement tells you whether it is singular or plural.

Inapaswa means something like it should, it is supposed to, or it ought to.

It can be broken down like this:

• i- = subject marker for class 9 singular
• -na- = present tense
• -paswa = be supposed to / be required to / ought to

So barua hii inapaswa... literally means this letter is supposed to... or this letter should...

Depending on context, -paswa can sound:

• mild: should
• stronger: is supposed to
• sometimes fairly strong: must be

But in many learning contexts, should / is supposed to is the safest understanding.

Because the sentence means that the letter is the thing being read, not the thing doing the reading.

• kusoma = to read
• kusomwa = to be read

The -w- is the passive marker.

So:

• kusoma barua = to read a letter
• barua kusomwa = the letter to be read / for the letter to be read

In this sentence, barua hii inapaswa kusomwa means this letter should be read.

If you said barua hii inapaswa kusoma, that would wrongly suggest the letter should read, which does not make sense.

It is made from the verb root -som- meaning read.

Step by step:

• ku- = infinitive marker, like to
• -som- = read
• -w- = passive
• -a = final vowel

So:

• kusoma = to read
• kusomwa = to be read

This passive pattern is very common in Swahili:

• kuandika = to write

• kuandikwa = to be written

• kufungua = to open
• kufunguliwa = to be opened

Here it means aloud, not necessarily loudly.

Literally, kwa sauti is something like with voice or in a voice, but in natural English the best meaning here is aloud.

So:

• kusomwa kwa sauti = to be read aloud

If you wanted to emphasize loud volume, you would usually add something more, such as:

• kwa sauti kubwa = in a loud voice / loudly

So kwa sauti is about the fact that the reading is vocal, not silent.

Darasani means in the classroom or in class.

It comes from:

• darasa = classroom / class
• -ni = locative ending, often meaning in, at, or to

So:

• darasa = classroom
• darasani = in the classroom

This -ni ending is very common in Swahili for places:

• nyumba = house

• nyumbani = at home / in the house

• shule = school

• shuleni = at school

• meza = table
• mezani = on the table / at the table

The exact English preposition depends on context, but darasani here is best understood as in the classroom.

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

So barua can mean:

• a letter
• the letter
• letter

The context tells you which one is meant.

In this sentence, barua hii means this letter, so the demonstrative hii already makes it definite and specific. That is why no separate word for the is needed.

The given word order is natural and standard:

• Barua hii = topic/subject
• inapaswa kusomwa = should be read
• kwa sauti = aloud
• darasani = in the classroom

So:

Barua hii inapaswa kusomwa kwa sauti darasani.

Swahili word order is often fairly flexible, especially with adverbial phrases like kwa sauti and darasani, but not all versions sound equally natural in all contexts.

For example, these may also be possible depending on emphasis:

• Barua hii inapaswa kusomwa darasani kwa sauti.
• Darasani, barua hii inapaswa kusomwa kwa sauti.

But the original version is a very normal neutral way to say it.

Yes, but the nuance changes.

• inapaswa = should / is supposed to / ought to
• lazima = must / it is necessary that

A stronger version would be something like:

• Barua hii lazima isomwe kwa sauti darasani.

Notice that with lazima, Swahili often uses a finite passive verb like isomwe rather than inapaswa kusomwa.

So:

• Barua hii inapaswa kusomwa... = this letter should be read...
• Barua hii lazima isomwe... = this letter must be read...

The first is usually less forceful than the second.

Because this sentence uses the pattern -paswa + infinitive.

That pattern works like this:

• X inapaswa kufanya... = X should do...
• X inapaswa kufanywa... = X should be done...

So here:

• inapaswa = should
• kusomwa = to be read

Together: should be read

By contrast, isomwe is a different construction. It is a passive subjunctive form, often used after words like lazima, ni lazima, or in certain formal instructions.

So both are possible in the right contexts, but they are built differently:

• Barua hii inapaswa kusomwa...
• Barua hii lazima isomwe...

Because barua is one of those nouns whose singular and plural forms look the same.

So the noun itself does not change:

• singular: barua
• plural: barua

What changes is the agreement:

Singular:

• barua hii
• inapaswa

Plural:

• barua hizi
• zinapaswa

So in your sentence, the singular agreement hii and i- show clearly that it means this letter, not these letters.

Yes, it sounds fairly formal or instructional.

A sentence like Barua hii inapaswa kusomwa kwa sauti darasani would fit well in contexts such as:

• school instructions
• official notices
• written guidelines
• textbook examples

In casual conversation, people might choose a simpler or more direct way of saying something similar, depending on the context. But the sentence itself is completely natural and correct.

Yes.

Like many Swahili locative forms, darasani can be translated in more than one way depending on context:

• in class
• in the classroom
• during class in some situations

In your sentence, the most natural understanding is probably in the classroom or in class:

• This letter should be read aloud in class.
• This letter should be read aloud in the classroom.

Both are good translations depending on what meaning has already been given to the learner.

A useful way to see it is:

Barua hii + inapaswa + kusomwa + kwa sauti + darasani

That gives:

• Barua hii = this letter
• inapaswa = should / is supposed to
• kusomwa = be read
• kwa sauti = aloud
• darasani = in the classroom

So the full pattern is:

[subject] + [should] + [passive infinitive] + [manner] + [place]

This is a very helpful pattern to recognize in other sentences too.