Mkia wa paka wetu ni mrefu kuliko wa mbwa mdogo.

Here wa is the associative/linking word that often corresponds to of in English.

So:

• mkia wa paka wetu = the tail of our cat

It is not a fixed word that is always wa. It changes depending on the noun class of the thing being possessed. Since mkia is singular and belongs to the m-/mi- class, the linker is wa.

In Swahili, the noun usually comes first, and words that describe or limit it come after it.

So:

• paka wetu = our cat
• not wetu paka

This same pattern is very common:

• mbwa mdogo = small dog
• kitabu changu = my book
• watoto wawili = two children

So the order is much more like noun + modifier than in English.

This is because paka is an animate noun. In Swahili, animals and people often take animate agreement with adjectives, possessives, and some other modifiers, even if their noun class might make you expect something else.

So:

• paka wetu = our cat
• mbwa wetu = our dog

This is why you also get forms like:

• mbwa mdogo = small dog
• not mbwa ndogo

For many learners, this is one of the most important things to notice with animal nouns.

It refers to paka.

The phrase is grouped like this:

• mkia wa [paka wetu]

So it means:

• the tail of [our cat]

If wetu referred to mkia, the structure would need to be different. As written, wetu clearly goes with paka, because it comes right after it.

The basic adjective stem is -refu, meaning long. It has to agree with the noun it describes.

Here it describes mkia:

• mkia = tail

Since mkia is singular in the m-/mi- class, the adjective takes m-:

• mrefu = long

So:

• mkia ... ni mrefu = the tail ... is long

If it were plural, the agreement would change:

• mikia mirefu = long tails

Kuliko means than in comparisons.

A very common pattern is:

• X ni adjective kuliko Y
• X is more adjective than Y
• or more naturally in English, X is adjective-er than Y

So here:

• ni mrefu kuliko = is longer than

Swahili does not add an -er ending the way English does. Instead, it keeps the normal adjective and adds kuliko.

Because Swahili usually forms this kind of comparison with:

• adjective + kuliko

So:

• mrefu = long
• mrefu kuliko = longer than

The idea of comparison comes from kuliko, not from changing the adjective into a special comparative form.

Because Swahili can leave out a repeated noun when it is already understood from context.

The full version would be:

• Mkia wa paka wetu ni mrefu kuliko mkia wa mbwa mdogo.

But that repeats mkia, so the shorter version is more natural:

• Mkia wa paka wetu ni mrefu kuliko wa mbwa mdogo.

In English, this is similar to saying:

• the tail of our cat is longer than that of the small dog

Here wa mbwa mdogo means something like that of the small dog, with mkia understood.

Because it agrees with the understood noun mkia, not with mbwa.

So after kuliko, the hidden full phrase is:

• mkia wa mbwa mdogo

Since the omitted noun is still mkia, the associative linker stays wa.

This is an important point: the wa there does not mean it is agreeing with mbwa. It is agreeing with the missing head noun mkia.

Again, this is because mbwa is an animate noun.

The adjective stem is -dogo = small. With animate singular agreement, it becomes:

• mdogo

So:

• mbwa mdogo = small dog

Even though mbwa belongs to the noun type that often has no visible singular/plural change, animate nouns frequently use the same kind of agreement as people do.

Ni here works like is.

It links the subject phrase to the description:

• Mkia wa paka wetu = subject
• ni mrefu = is long
• kuliko wa mbwa mdogo = than that of the small dog

So the middle of the sentence:

• ni mrefu means:
• is long

And with kuliko, the whole predicate becomes:

• is longer than ...

Yes. You can say:

• Mkia wa paka wetu ni mrefu kuliko mkia wa mbwa mdogo.

That is completely grammatical.

The version without the repeated noun:

• Mkia wa paka wetu ni mrefu kuliko wa mbwa mdogo.

is simply shorter and often more natural.

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

So a noun like paka can mean:

• a cat
• the cat

depending on context.

The same is true in this sentence. English needs an article, but Swahili does not.