Learn Hardcore German: Grundsätzlich gilt: Wer zu spät kommt, wartet draußen. - Basically this applies: whoever comes late waits outside.

Grundsätzlich = generally, as a rule, in principle.
gilt is 3rd-person singular of gelten (“to be valid/apply/hold true”). It’s used impersonally here: the implied subject is es (“Es gilt: …”), which can be omitted. So: “As a general rule applies: …” → “As a rule: …”

Why is there a colon after gilt, and is Wer capitalized correctly?

The colon introduces the rule that follows.
In German, if what follows a colon is a full sentence, the first word is capitalized. Wer starts a new independent sentence, so it’s capitalized. (Even aside from that, it’s sentence-initial.)

What exactly is wer here?

wer is a “free relative” pronoun meaning “whoever/those who.” It stands in for a generic person and is the subject of kommt (nominative).
Rough equivalents: jeder, der … (“everyone who …”) or English “whoever.”
Case forms: nominative wer, accusative wen, dative wem, genitive wessen.

Could I use wenn instead of wer?

Yes, but it slightly changes the feel:
- Wer zu spät kommt, wartet draußen. = “Whoever comes late …”
- Wenn man zu spät kommt, wartet man draußen. = “If/when you come late, you wait outside.”
wer generalizes over “whoever”; wenn expresses a condition for an unspecified “man/you.”

Why does wartet come right after the comma?

German main clauses are verb-second. The entire Wer zu spät kommt clause occupies position 1; the finite verb wartet must be in position 2. Hence: “Wer zu spät kommt, [2] wartet draußen.”

Why is there a comma between the two parts?

Subordinate (dependent) clauses in German are separated by commas. Wer zu spät kommt is such a clause; the comma is mandatory.

Why is the verb singular (wartet) when multiple people might be late?

With wer, German uses singular agreement. If you want plural agreement, rephrase:
- Alle, die zu spät kommen, warten draußen.

Does zu spät mean “too late”? Isn’t that stronger than just “late”?

Literally, zu spät is “too late,” but the fixed expression zu spät kommen simply means “to be late/arrive late” to something. It does not necessarily imply it’s hopelessly late.
- Ich komme zu spät. = “I’m going to be late.”
- Ich komme spät. can mean “I’ll come late (at a late time),” but for punctuality relative to a set time, zu spät is the idiomatic choice.

Why kommt and not ankommt?

The idiomatic collocation for people is zu spät kommen.
zu spät ankommen is common for scheduled things (trains, flights) and is also possible for people, but kommen is the default for “arrive late (to an event/meeting).”

Should it be wartet auf instead of just wartet?

warten can be intransitive: Er wartet draußen. = “He waits outside.”
Use auf only when you name what you’re waiting for: Er wartet draußen auf den Lehrer.

What does draußen mean exactly, and how is it different from außen or vor der Tür?

draußen = outside (as a location, not inside): Sie wartet draußen.
außen = on the outside/exterior surface: außen am Gebäude (“on the outside of the building”).
vor der Tür = specifically “outside the door / in front of the door,” often clearer for rooms.
Direction vs. location: draußen (location), nach draußen/raus (movement: “to the outside”).

Why is it spelled draußen with ß? What about Switzerland?

After a long vowel/diphthong, German uses ß: au → draußen. In Switzerland/Liechtenstein, ß is not used; you’ll see draussen.

Could I say Wer zu spät ist instead of Wer zu spät kommt?

It’s possible, but zu spät kommen is the standard idiom for arriving late to something. Wer zu spät ist emphasizes the state of being late rather than the act of arriving late, and sounds less natural in a rule like this.

Can I add der after the comma (Wer …, der …)?

Yes. This is a common emphatic pattern: Wer zu spät kommt, der wartet draußen. The der is optional and doesn’t change the meaning.

How is gelten conjugated, and what’s its past?

Present: ich gelte, du giltst, er/sie/es gilt, wir gelten, ihr geltet, sie gelten.
Simple past: galt; Perfekt: hat gegolten.
Meaning: “to be valid/apply/hold.” Example: Die Regel gilt für alle.

Can I write it without the colon?

Prefer keeping the colon here. If you want to avoid it, rephrase:
- Die Grundregel lautet, dass alle, die zu spät kommen, draußen warten.
- Im Allgemeinen gilt, dass alle, die zu spät kommen, draußen warten.
A literal “Grundsätzlich gilt, dass wer …” is grammatical but stylistically clunky.

What’s the tone/register of this sentence?

Neutral to mildly strict. It sounds like a posted rule (classroom, meeting, event). Alternatives with similar tone: Generell gilt:, Im Prinzip gilt:, Die Regel lautet:.