Kakawalis lang ni Maria ng sahig sa kusina.

Kakawalis uses the prefix kaka- with the root walis. This pattern expresses a recently completed action: something that was done just now / just a moment ago.

So kakawalis is roughly like:

• has just swept
• just swept

It is not the ordinary simple past form. It specifically adds the idea of very recent completion.

Both can refer to a completed action, but they are not the same.

• Nagwalis si Maria... = Maria swept...
• Kakawalis lang ni Maria... = Maria has just swept... / Maria just swept...

The kaka- form emphasizes that the action happened very recently. If you use nagwalis, you are simply stating that the sweeping happened, without that strong just now feeling.

Here lang means just, in the sense of just recently.

So in this sentence, lang does not mainly mean only. Instead, it strengthens the recent meaning of kakawalis.

Compare:

• kakawalis lang = just swept
• In other contexts, lang can mean only, but here the time sense is the natural one.

That is one of the things learners often notice first.

In this kaka- recent-completive construction, the doer is commonly marked with ni if it is a personal name:

• ni Maria
• ni Juan

This is different from a more straightforward verbal sentence like:

• Nagwalis si Maria ng sahig.

So with kakawalis lang, ni Maria is the expected form in this pattern.

If you want to make Maria the topic, you can also say:

• Si Maria ay kakawalis lang ng sahig sa kusina.

Ng marks sahig as a non-topic common noun in the sentence.

Here, ng sahig is the thing affected by the action: the thing that got swept.

So:

• ng sahig = the floor as the thing being swept

This is normal in Filipino. English speakers often want to map everything directly to subject/object, but Filipino case marking works differently. What matters is the sentence pattern and which noun is being treated as the topic.

Because ni and ng are related markers, but they are used for different kinds of nouns:

• ni is used for personal names
• ng is used for common nouns

So:

• ni Maria = personal name
• ng sahig = common noun

Even though both belong to the same general case set, they mark different noun types. That is why seeing both in one sentence is completely normal.

Most naturally, sa kusina describes sahig:

• ng sahig sa kusina = the floor in the kitchen

But in practice, it also matches the location of the action, so the overall meaning is still that the sweeping happened in the kitchen.

So the phrase can feel like:

• the kitchen floor or
• the floor in the kitchen

Because sa kusina is a prepositional phrase, and Filipino does not use a linker before that kind of phrase.

You use linkers like -ng or na in combinations such as:

• malinis na sahig
• kahoy na mesa

But with a phrase like sa kusina, no linker is needed:

• sahig sa kusina

So this structure is completely normal.

No. A Filipino sentence does not always need an overt ang phrase.

This sentence is already complete as:

• Kakawalis lang ni Maria ng sahig sa kusina.

However, you can add a topic if you want a different emphasis. For example:

• Si Maria ay kakawalis lang ng sahig sa kusina.

That version highlights Maria as the topic, but the original sentence is perfectly fine on its own.

Yes, it can, but lang is very common with this construction because it makes the just now meaning sound more natural.

So:

• Kakawalis ni Maria ng sahig sa kusina.
  is possible, but
• Kakawalis lang ni Maria ng sahig sa kusina.
  sounds more idiomatic for Maria has just swept the floor in the kitchen.

In everyday speech, learners will often hear kaka- + verb + lang together.