Learn Hardcore Swahili: Wakati tunasoma, ubongo wetu hutumia nishati nyingi. - When we study, our brain uses a lot of energy.

Wakati means “when” and introduces a time clause. In Swahili you place wakati before the subject and verb of the subordinate clause (here tunasoma). It marks the time frame in which the main action happens.

How is the verb tunasoma formed, and why is it written as one word?

Swahili verbs are single words composed of:

A subject prefix (tu- for “we”)
A tense/aspect marker (-na- for present)
The verb root (-soma for “read”)

Putting them together gives tu + na + soma = tunasoma, meaning “we are reading”.

Why is it ubongo wetu and what does the suffix -etu do?

Ubongo means “brain.” The suffix -etu attaches to class 11 nouns (those beginning with u-) to mean “our.” So ubongo wetu literally is “our brain.”

Why is the verb hutumia used here instead of tunatumia or inatumia?

The subject of “uses” is ubongo wetu (our brain), not sisi (we).

Ubongo belongs to noun class 11, whose subject prefix is u-.
In the simple/habitual present that prefix appears as hu- (no separate -na-).

Thus hu + tumia = hutumia, meaning “it (the brain) uses.”

What kind of noun is nishati, and why is the adjective nyingi used?

Nishati (“energy”) is in noun class 9/10. Adjectives must agree with the noun class:

The root -ingi (“many/much”) gains the class 9/10 prefix ny-, becoming nyingi.
So nishati nyingi = “a lot of energy.”

Could I say tunaposoma instead of wakati tunasoma? What’s the difference?

Yes. Tunaposoma (= tu + -po- + na + soma) also means “when we read.”

tunaposoma uses the -po- infix to mark “when.”
wakati tunasoma uses the separate word wakati.

Both are correct; tunaposoma is more concise, while wakati tunasoma is more explicit.