Learn Hardcore Finnish: Hän tulee kotiin myöhään, koska bussi on myöhässä. - He/She comes home late because the bus is late.

Yes, it can often be left out. Finnish verb endings usually show the subject, so (hän) tulee is often just tulee in context. Hän is kept when you want to clarify who (he/she) you mean, add emphasis, or avoid ambiguity.

What tense is tulee? Is it present or future?

Formally it’s the present tense (tulee = comes/is coming), but Finnish present tense very commonly covers near-future meaning too. So it can mean he/she comes (later) / is coming / will come, depending on context.

Why is it kotiin and not koti or kotona?

Kotiin is the illative case and means into/to home (movement toward home).

kotiin = to home (destination)
kotona = at home (location, no movement)
koti is the basic dictionary form (home), used as a subject/object, not to express “to home” by itself.

What exactly does kotiin mean—“to the house” or “to home”?

Usually kotiin is best understood as home (as a place of belonging), not specifically a building. It’s like English go home rather than go to the house. If you specifically mean the building, Finnish might use taloon (into the house) or talolle (to the house/yard), depending on the idea.

Why is there a comma before koska?

In Finnish, it’s standard to separate a main clause and a subordinate clause with a comma. koska (because) introduces a subordinate clause, so you write: main clause, koska subordinate clause.

Does koska always mean “because”? I’ve seen it used differently.

In statements like this, koska means because/since (reason). In some contexts, especially in questions, koska can relate to time like since when (e.g., Koska olet ollut täällä? = Since when have you been here?). But in your sentence it’s clearly causal: because the bus is late.

Why is it myöhään in the first clause but myöhässä in the second?

They’re different adverbial forms with different typical uses:

myöhään = late (at a late time), answering “when?” (time)
→ tulee kotiin myöhään = comes home late
myöhässä = late (behind schedule), answering “in what state/condition?”
→ bussi on myöhässä = the bus is late (delayed)

What case is myöhässä? Why does it end in -ssä?

myöhässä is the inessive case (-ssa/-ssä), literally something like in lateness. Finnish often uses location cases metaphorically for states. So olla myöhässä (to be late) is an idiomatic “state” expression.

Is olla myöhässä the main way to say “to be late”?

Yes, olla myöhässä is the standard, everyday way to say a person/vehicle/event is late (delayed). For arriving late somewhere, you can also say tulla myöhässä (to come late), but olla myöhässä is the most common general pattern.

Why is the word order Hän tulee kotiin myöhään and not something else? Can I move words around?

This order is neutral and natural: subject + verb + destination + time adverb. Finnish word order is flexible, but changes emphasis:

Hän tulee kotiin myöhään. (neutral)
Myöhään hän tulee kotiin. (emphasizes late)
Kotiin hän tulee myöhään. (emphasizes home as the destination)
The meaning stays similar, but the focus shifts.

Why is it bussi on myöhässä (present)? Wouldn’t English sometimes use “the bus was late” depending on timing?

Finnish uses present tense when the delay is still relevant “now” as the reason for being late. If you’re talking about a completed past situation, you can use past tense: bussi oli myöhässä (the bus was late).

Does hän mean “he” or “she”? How do I know which one?

hän means both he and she (and sometimes they for a person respectfully in some dialects, though standard plural is he). You infer gender from context, a name, or additional information—Finnish pronouns generally don’t mark gender.