Sa pagdating ni Tatay, magsisimula na tayo.

This phrase means upon Dad’s arrival or when Dad arrives.

• sa is a preposition that often means in, at, on, or upon, depending on context.
• pagdating is a noun-like form from the verb dating / dumating (to arrive).
• Together, sa pagdating means something like at the arrival or upon arriving.

So Sa pagdating ni Tatay sets the time for the main action: when Dad arrives.

Pagdating is a verbal noun or action noun. It refers to the act of arriving.

It comes from the root idea dating/datingan related to arrival, and in actual usage pagdating often means:

• arrival
• upon arriving
• when someone arrives

In this sentence, it functions like a time expression rather than a full verb. That is why the sentence does not use a separate verb for Dad arrives. Instead, it uses the phrase sa pagdating ni Tatay.

Because Tatay is not the subject of the main clause here. He is the one associated with the noun pagdating (arrival), so Filipino uses ni.

Compare the roles:

• si Tatay = Dad as a topic/subject
• ni Tatay = of Dad / Dad’s

So pagdating ni Tatay literally means Dad’s arrival.

That is why ni is correct here.

Magsisimula means will start or will begin.

It comes from the root simula (beginning / start) with the actor-focus future form:

• mag-
  • reduplication of the first syllable + root
• mag + si + simula → magsisimula

This is a very common future pattern for mag- verbs.

So:

• magsisimula = will start
• nagsisimula = is starting / starts
• nagsimula = started

Na is a very common particle in Filipino. Here it adds the sense of already, now, or at that point.

In this sentence, magsisimula na tayo suggests:

• we’ll start now
• we’ll begin already
• we’ll begin then

It often gives a feeling that the action is expected, timely, or about to happen.

Without na, magsisimula tayo simply means we will start. With na, it sounds more like we’ll start then / we’ll start already.

Because tayo means we, including the person being spoken to.

Filipino distinguishes between:

• tayo = we including you
• kami = we excluding you

So magsisimula na tayo means the speaker is including the listener in the group that will start.

If the speaker meant we, but not you, it would be magsisimula na kami.

More or less, yes. A very literal breakdown would be:

• Sa = at/upon
• pagdating = arrival / arriving
• ni Tatay = of Dad / Dad’s
• magsisimula = will start
• na = already / now / then
• tayo = we including you

So a literal gloss is something like:

Upon Dad’s arrival, we will start already.

But in natural English, this is usually expressed as:

• When Dad arrives, we’ll start.
• We’ll begin when Dad gets here.

Tatay specifically means Dad or Daddy. It is a common Filipino word for father, especially in family speech.

Other related words include:

• ama = father, more formal/literary
• tatay = dad
• papa = papa/dad

In this sentence, Tatay is being used like a title or family name for the person, so it is capitalized.

Because ni Tatay is not describing pagdating as an adjective would. It marks possession or association.

This is a genitive construction:

• pagdating ni Tatay = Dad’s arrival

No linker is needed there.

Linkers such as na or -ng are used in structures like:

• mabait na bata = kind child
• malaking bahay = big house

But ni Tatay is not an adjective phrase, so the linker is not used.

Yes. Filipino has several ways to express when.

Possible alternatives include:

• Pagdating ni Tatay, magsisimula na tayo.
• Kapag dumating si Tatay, magsisimula na tayo.
• Pag dumating si Tatay, magsisimula na tayo.

These are similar, but not identical in feel:

• Sa pagdating ni Tatay sounds a bit like upon Dad’s arrival
• Pagdating ni Tatay is also very natural and common
• Kapag dumating si Tatay is more explicitly when Dad arrives
• Pag dumating si Tatay is a very common conversational form

So the original sentence is correct, but there are other natural ways to say the same idea.

Because Filipino commonly places the predicate first.

In English, we usually say:

• We will start

In Filipino, it is very common to say:

• Magsisimula tayo

So the verb or predicate often comes before the topic or pronoun.

This is normal Filipino sentence structure, and learners should get used to seeing:

• Aalis ako = I will leave
• Kakain siya = He/She will eat
• Magsisimula tayo = We will start

Yes. Even though pagdating is noun-like, the whole phrase can still refer to a future time depending on context.

In this sentence, the future meaning is clear because the main clause uses the future verb magsisimula.

So sa pagdating ni Tatay is understood as:

• when Dad arrives
• upon Dad’s arrival

not when Dad arrived.

Context and the tense/aspect of the main verb help determine the time reference.

Yes, it is natural and correct. It sounds slightly neat or orderly, but still very normal.

In everyday speech, people might also say:

• Pagdating ni Tatay, magsisimula na tayo.
• Pag dumating si Tatay, magsisimula na tayo.

So the given sentence is perfectly acceptable, just with a slightly more structured feel because of sa pagdating.