Kiota cha ndege kiko juu ya mti.

Because the of/possessive linker in Swahili agrees with the noun being possessed, not with the owner.

Here, kiota means nest and belongs to the ki-/vi- noun class. For that class, the linker is cha.

So:

• kiota cha ndege = the nest of a bird / bird’s nest

If the main noun were in a different class, the linker would change:

• mti wa ndege = the bird’s tree
• kitabu cha mwanafunzi = the student’s book
• nyumba ya mwalimu = the teacher’s house

So cha is there because of kiota.

That is noun class agreement.

Kiota is a noun in the ki-/vi- class. In Swahili, other words connected to that noun often have to match its class. The ki- in kiko is the agreement marker showing that the thing being talked about is a class 7 noun.

So:

• kiota = nest
• ki- in kiko = agreement with kiota

This kind of matching is very common in Swahili and is one of the most important grammar patterns to learn.

Kiko means something like it is there / it is located for a noun in the ki-/vi- class.

It is not just a general is. It is specifically a locational form, used when saying where something is.

So in this sentence, kiko introduces the location of the nest.

Compare:

• Kiota kiko juu ya mti. = The nest is on top of / up in the tree.
• Kitabu kiko mezani. = The book is on the table.

This is why Swahili often uses forms like kiko, uko, ziko, wako, etc., depending on the noun class.

Because ni and kiko are used differently.

Ni is often used to identify or equate things:

• Huyu ni mwalimu. = This is a teacher.
• Kiota ni kikubwa. = The nest is big.
  (More literally, this is a statement about what it is like.)

But for location, Swahili commonly uses locative forms like kiko:

• Kiota kiko juu ya mti. = The nest is above/on the tree.

So a learner can think of it this way:

• ni = identity / description
• kiko = location

Ndege can mean bird or birds. The form is the same in singular and plural.

In this sentence, the most natural interpretation is singular:

• kiota cha ndege = bird’s nest / nest of a bird

But grammatically, ndege itself does not change form. Context tells you whether it is singular or plural.

This happens with many nouns in the N-class in Swahili.

Because juu usually connects to the following noun with ya.

So:

• juu ya mti = on top of the tree / above the tree

Many location expressions work like this:

• chini ya = under / below
• juu ya = above / on top of
• mbele ya = in front of
• nyuma ya = behind
• karibu na = near

So ya is part of the normal structure of this expression.

It can suggest either on top of or above/up in relation to the tree, depending on context.

Literally, juu ya mti is above the tree / on top of the tree. But in natural use, with something like a nest, English may translate it more naturally as:

• in the tree
• up in the tree
• high in the tree

So the Swahili phrase is a bit broader than one exact English wording.

Because Swahili does not usually use articles like English a/an and the.

So:

• kiota can mean a nest or the nest
• mti can mean a tree or the tree

Context tells you which one is meant.

This is very normal in Swahili, so English speakers often have to get used to reading nouns without articles.

The word order is:

Subject + locational verb form + location phrase

So here:

• Kiota = subject
• kiko = is located
• juu ya mti = above/on the tree

That makes the full structure:

• Kiota cha ndege = bird’s nest
• kiko juu ya mti = is on top of / up in the tree

So the whole sentence is built very straightforwardly.

Mti belongs to the m-/mi- class.

In this sentence, it does not control the main agreement, because the main subject is kiota, not mti. That is why the verb-like form is kiko, matching kiota.

However, if mti were the subject, the agreement would change. For example:

• Mti uko juu ya nyumba. = The tree is above the house.

So mti has its own agreement patterns, but here it is only inside the location phrase juu ya mti.

You would make the main noun plural and then change the agreeing words to match it:

• Kiota → viota
• cha → vya
• kiko → viko
• mti → miti if you mean more than one tree

So:

• Viota vya ndege viko juu ya miti. = The birds’ nests are on the trees.

This is a good example of how several words in a Swahili sentence change together because of noun class agreement.