Learn Hardcore Swahili: Mwalimu anasoma barua kwa sauti darasani. - The teacher reads the letter aloud in the classroom.

a- = 3rd person singular subject prefix (he/she)
na- = present tense marker
soma = verb root meaning “read”
Together a-na-soma literally means “he/she is reading” (or “he/she reads”).

Why doesn’t barua have a plural marker, and what noun class is it?

barua belongs to noun class 9/10, which often uses the same form for singular and plural.
Context indicates whether it’s “a letter” or “letters.”

What does kwa sauti mean literally, and what role does kwa play?

Literally kwa sauti = “with voice.”
kwa is an instrumental preposition here, indicating the means or manner (“by/with”).

How is darasani formed from darasa, and what does the suffix -ni indicate?

Start with darasa (classroom). Add the locative suffix -ni to show “in/at.”
So darasani = “in the classroom.”

Why is there no direct object marker in anasoma for barua, and when would you use one?

Object markers are optional when the object noun is explicitly stated.
You could include it for emphasis or brevity, e.g. Mwalimu anaisoma barua, but Swahili often omits it if the object follows the verb.

Why are there no articles like “the” or “a” in the sentence?

Swahili doesn’t use separate articles. Nouns stand alone, and context tells you if they’re definite or indefinite.

What is the usual word order for adverbial phrases like kwa sauti and locatives like darasani in Swahili?

Typical order is: Subject – Verb – Object – Manner (instrumental adverb) – Place (locative).
Hence Mwalimu anasoma barua (S-V-O), then kwa sauti (how), then darasani (where).

What is the plural form of mwalimu, and how does that fit into Swahili noun classes?

mwalimu is class 1 (singular). Replace the m- prefix with wa- for class 2 (plural): walimu (teachers).

If we wanted to emphasize that the teacher is reading right now (at this very moment), could we modify anasoma? How?

You could use the perfect-progressive construction:
Mwalimu amekuwa akisoma barua kwa sauti darasani.
Here amekuwa akisoma stresses ongoing action “has been reading.”

Could we use kwenye instead of the suffix -ni in darasani, and how would that change the sentence?

Yes. You’d say:
Mwalimu anasoma barua kwa sauti kwenye darasa.
Both mean “in the classroom,” but darasani (-ni) is more concise, while kwenye darasa uses the preposition kwenye plus noun.