Learn Hardcore Filipino: Kapag mainit sa hapon, magpahinga tayo sa bahay at huwag mag-alala. - When it's hot in the afternoon, let's rest at home and don't worry.

Kapag means “when/whenever” and is used for real, time-based or regularly occurring conditions: Kapag mainit sa hapon... (“When it’s hot in the afternoon...”).
Kung is “if” and often sounds more hypothetical or uncertain. Many speakers use them interchangeably in casual speech, but the neutral, time-linked choice here is kapag.
You could say Kung mainit sa hapon... and be understood, but kapag is the more natural choice for “when” in this context.

Can I shorten kapag to ’pag?

Yes. In informal writing/speech, ’pag is a common contraction of kapag:

’Pag mainit sa hapon, ... Use the apostrophe to show it’s a contraction. In formal writing, keep kapag.

Does sa hapon mean “in the afternoon” or “this afternoon”?

Here it means “in the afternoon” (general time of day). For “this afternoon,” say mamayang hapon:

Kapag mainit mamayang hapon, ... (“If it’s hot this afternoon, ...”)

Why is it sa hapon and not ng hapon?

Use sa for general time expressions: sa umaga (in the morning), sa hapon (in the afternoon), sa gabi (at night).
Use ng hapon mostly when modifying a specific time or noun: Alas dos ng hapon (2 PM), meeting ng hapon (the afternoon meeting). So mainit sa hapon = “hot in the afternoon” (general).

There’s no explicit “it” in Kapag mainit sa hapon. Is that okay?

Yes. Tagalog often uses adjective-first clauses without an explicit subject for weather or states:

Mainit sa hapon literally “Hot in the afternoon.” If you want an explicit subject, you can say: Kapag mainit ang panahon sa hapon, ... (“When the weather is hot in the afternoon, ...”)

What exactly is magpahinga?

Root: pahinga (“rest”).
Verb (actor-focus) with mag-: magpahinga (“to rest”).
Aspects:
- Completed: nagpahinga (rested)
- Progressive: nagpapahinga (is/are resting)
- Contemplated: magpapahinga (will rest)
In Magpahinga tayo, the bare mag- form functions as a suggestion/imperative: “Let’s rest.”

Why is it tayo and not kami?

Tayo = “we/us” inclusive (speaker + listener). It invites the listener: “Let’s (you and I) rest.”
Kami = “we/us” exclusive (speaker + others, not the listener). You wouldn’t use kami for “let’s.”

Is Magpahinga tayo the normal way to say “Let’s rest”?

Yes. It’s the standard hortative. You can soften or nuance it with clitics:

Magpahinga muna tayo. (Let’s rest first.)
Magpahinga na tayo. (Let’s rest now/already.)
Magpahinga na lang tayo. (Let’s just rest.)

Where can tayo go in the sentence?

Common placements:

Magpahinga tayo sa bahay. (neutral)
Sa bahay tayo magpahinga. (emphasizes the place)
Formal/literary: Tayo’y magpahinga sa bahay. Avoid tayo magpahinga sa bahay without a linker; it sounds incomplete in modern style.

Does sa bahay mean “at home” or “at the house”?

Usually “at home.” If you mean a specific house, specify it:

sa bahay namin (at our house)
sa bahay ni Maria (at Maria’s house) On its own, sa bahay typically implies staying at home.

What does at do here? Could I use something else?

At is “and.” In casual speech, you’ll also hear tsaka/saka (“and then/and also”):

... sa bahay tsaka huwag mag-alala. At is the neutral, safe connector in writing.

Is huwag the same as wag?

Huwag is the standard spelling. Wag (or ’wag) is very common in informal writing/texting. In careful or formal writing, prefer huwag.

Who is being told “don’t worry” in huwag mag-alala?

With no pronoun, it’s a general “don’t worry.” To be explicit:

To one person: Huwag kang mag-alala.
To several people: Huwag kayong mag-alala.
Inclusive “let’s not”: Huwag tayong mag-alala. If you want the whole sentence to be “let’s … and let’s not …,” say: Magpahinga tayo sa bahay at huwag tayong mag-alala.

Why is there a hyphen in mag-alala but not in magpahinga?

When a mag- verb attaches to a root that starts with a vowel, a hyphen is commonly used for readability: mag-alala, mag-aral, mag-ayos. No hyphen is needed when the root starts with a consonant: magpahinga, maglakad.

Could I say magpapahinga tayo instead of magpahinga tayo?

Magpapahinga tayo = “We will rest” (a future statement/plan).
Magpahinga tayo = “Let’s rest” (suggestion/imperative). Use the bare mag- for the hortative “let’s.”

Is the comma after the kapag-clause required?

It’s standard and helpful: Kapag mainit sa hapon, ... You can also place the kapag-clause after the main clause without a comma:

Magpahinga tayo sa bahay at huwag mag-alala kapag mainit sa hapon.

Any polite or softer versions of the whole sentence?

Polite: Kapag mainit sa hapon, magpahinga po tayo sa bahay at huwag po tayong mag-alala.
Softer: Kapag mainit sa hapon, sa bahay na lang tayo magpahinga at huwag na tayong mag-alala muna. (adds “just,” “already,” “for now” nuances)

What’s the difference between hapon and tanghali?

Tanghali = midday/noon-ish period.
Hapon = afternoon (after tanghali until evening). So sa hapon is later than sa tanghali.