Asha hakuwa na sauti nzuri kwa sababu koo lake lilikuwa linauma.

Hakuwa na means did not have.

It is built from:

• ha- = negative marker
• -kuwa- = be
• na = with / have

In Swahili, to have is usually expressed as kuwa na, literally to be with.

So:

• alikuwa na = she had / she was with
• hakuwa na = she did not have / she was not with

Because the subject is Asha (a person, noun class 1), the positive subject marker would be a- (she), but in the negative past it becomes hakuwa.

In Swahili, possession is often expressed with kuwa na, literally to be with.

So instead of a single verb exactly like English have, Swahili often uses:

• nina kitabu = I have a book
• literally: I am with a book

In this sentence:

• Asha hakuwa na sauti nzuri
  = Asha did not have a good voice

So na is an important part of the expression for possession here.

The adjective has to agree with the noun class of sauti.

• sauti = voice, and it belongs to the N-class (class 9/10)
• The adjective stem is -zuri = good / nice
• In this noun class, it becomes nzuri

So:

• sauti nzuri = a good voice

This agreement is very common in Swahili:

• mtu mzuri = a good person
• jicho zuri = a good eye
• sauti nzuri = a good voice

Kwa sababu means because.

It introduces a reason:

• Asha hakuwa na sauti nzuri kwa sababu... = Asha did not have a good voice because...

You can think of it as a fixed expression meaning because / for the reason that.

In Swahili, possessives usually come after the noun.

So:

• koo lake = her throat
• literally: throat her

Also, the possessive must agree with the noun class of koo.

• koo belongs to noun class 5
• the possessive form for her / his in this class is -lake

That is why we get:

• koo lake = her throat

Other examples:

• kitabu chake = his/her book
• jina lake = his/her name
• mikono yake = his/her hands

Because the verb must agree with the noun class of the subject.

Here, the subject is koo (throat), which is class 5.
The class 5 subject marker is li-.

So:

• koo lake lilikuwa... = her throat was...
• koo lake linauma = her throat hurts

That is why you see li- in both:

• lilikuwa
• linauma

This is normal Swahili agreement: verbs match the noun class of their subject.

Lilikuwa linauma means was hurting or was painful.

It is made of:

• lilikuwa = it was
• linauma = it hurts / is hurting

Together, this creates a past continuous-type meaning:

• lilikuwa linauma = it was hurting

So:

• koo lake lilikuwa linauma = her throat was hurting

This structure is very common in Swahili:

• alikuwa anasoma = he/she was reading
• walikuwa wanacheza = they were playing
• lilikuwa linauma = it was hurting

You could say koo lake liliuma, and it would mean something like her throat hurt.

But lilikuwa linauma gives more of a sense of an ongoing condition:

• liliuma = hurt
• lilikuwa linauma = was hurting / had been hurting

In this sentence, the longer form fits well because it explains a continuing reason for her bad voice.

Kuuma usually means to hurt, to ache, or sometimes to bite, depending on context.

Here it clearly means to hurt / ache:

• koo linauma = the throat hurts
• kichwa kinauma = the head hurts
• jino linauma = the tooth hurts

So in this sentence, linauma means it hurts / it is hurting.

In Swahili, the subject is usually shown inside the verb, so a separate pronoun is often unnecessary.

For a person like Asha, the verb already shows the subject:

• alikuwa = she was
• hakuwa = she was not

Since the sentence already names the subject as Asha, adding a separate pronoun would usually be unnecessary.

So:

• Asha hakuwa na sauti nzuri is perfectly normal.

Yes. Sauti nzuri literally means good voice, and it is natural Swahili.

Depending on context, it can mean:

• a pleasant voice
• a clear voice
• a nice singing or speaking voice

In this sentence, because the next part says her throat was hurting, it suggests her voice did not sound good at that time.

Because the subject changes.

In the first part, the subject is Asha, a person:

• Asha hakuwa na sauti nzuri
• the verb agrees with a human singular subject

In the second part, the subject is koo lake:

• koo lake lilikuwa linauma
• now the verb agrees with koo, which is class 5

So the agreement changes because the grammatical subject changes.

Yes, that would be a very natural English translation.

Literally, the Swahili says:

• Asha did not have a good voice because her throat was hurting

But idiomatic English might say:

• Asha didn’t sound good because her throat was hurting

So the Swahili structure is slightly different from natural English, but the meaning is the same.