Mtoto amesema ameshiba, kwa hiyo hataki biskuti tena.

A natural word-by-word breakdown is:

• Mtoto = child / the child
• amesema = has said / said
• ameshiba = is full / has eaten enough
• kwa hiyo = therefore / so / because of that
• hataki = does not want
• biskuti = biscuit / cookie
• tena = again / anymore, depending on context

So the sentence structure is basically:

• The child has said (that) he/she is full, so he/she does not want any more biscuits.

Because Swahili is expressing two linked ideas:

1. amesema = has said
2. ameshiba = is full / has become full

So Mtoto amesema ameshiba literally means:

• The child has said [that] he/she is full.

The first verb reports speech, and the second gives the content of what was said.

The prefix ame- is a very common perfect marker, often corresponding to English has + past participle or sometimes a present result:

• amesema = has said
• ameshiba = has become full / is full now

In Swahili, the word kwamba can mean that in sentences like this, but it is often omitted.

So both of these are possible:

• Mtoto amesema ameshiba
• Mtoto amesema kwamba ameshiba

Both mean:

• The child has said that he/she is full.

Leaving out kwamba is very normal and natural.

Not exactly. Ameshiba comes from the idea of being full or satisfied from eating.

So it usually means:

• he/she is full
• he/she has had enough to eat

It does not simply mean has eaten.
If you wanted just has eaten, you would normally use a form of kula:

• amekula = he/she has eaten

Compare:

• amekula = he/she has eaten
• ameshiba = he/she is full / has eaten enough

Hataki is the negative present form of anataka:

• anataka = he/she wants
• hataki = he/she does not want

This is a very common pattern in Swahili. In the present tense, negation often changes the verb form rather than simply adding a separate word like English not.

So:

• hataki biskuti = he/she does not want biscuits

Swahili does not have articles like English a/an/the.

So mtoto can mean:

• a child
• the child

The exact meaning depends on context.

Likewise, biskuti can mean:

• a biscuit
• biscuits
• the biscuit(s)

In this sentence, context makes it clear that English naturally translates it as the child and biscuits / any more biscuits.

Yes, it is very common. Kwa hiyo means:

• so
• therefore
• because of that
• as a result

In this sentence:

• ameshiba, kwa hiyo hataki biskuti tena
• he/she is full, so he/she does not want any more biscuits

It is a very useful connector for showing result or consequence.

Tena often does mean again, but in negative sentences it can also mean any more / any longer.

Here:

• hataki biskuti tena = he/she does not want biscuits anymore / any more biscuits

So in this sentence, tena is best understood as:

• any more
• any longer

Compare:

• Njoo tena = Come again
• Sitaki tena = I don’t want any more

Some Swahili nouns, especially many loanwords, do not change much between singular and plural in everyday usage. Biskuti is one of them.

So biskuti can refer to:

• a biscuit
• biscuits

Context tells you which one is meant.

In this sentence, because of tena and the overall meaning, English naturally understands it as any more biscuits.

The subject is carried through by the verb forms.

• Mtoto = the child
• amesema = the child has said
• ameshiba = the child is full
• hataki = the child does not want

The verb forms all point back to the same third-person singular subject: the child.

If needed, English repeats the pronoun:

• The child has said that he/she is full, so he/she does not want any more biscuits.

In Swahili, repeating the noun or pronoun is often unnecessary because the verb already shows the subject.

Yes. Mtoto belongs to the M-WA noun class for human beings:

• singular: mtoto = child
• plural: watoto = children

This noun class affects agreement on verbs. For singular human nouns like mtoto, the subject marker is a- in positive forms:

• mtoto anataka = the child wants
• mtoto amesema = the child has said
• mtoto ameshiba = the child is full

So the a- in these verbs agrees with mtoto.

Yes. A few small variations are possible:

• Mtoto amesema kwamba ameshiba, kwa hiyo hataki biskuti tena.

  • Adds kwamba = that

• Mtoto amesema ameshiba, hivyo hataki biskuti tena.

  • Uses hivyo instead of kwa hiyo, still meaning so / therefore

• Mtoto ameshiba, kwa hiyo hataki biskuti tena.

  • Removes amesema if you just want: The child is full, so he/she doesn’t want any more biscuits.

The original sentence is completely natural and clear.