Learn Hardcore Finnish: Menen metrolla keskustaan ja jään laiturille odottamaan. - I go by metro to the city center and stay on the platform to wait.

Yes. -lla/-llä (the adessive case) often marks the means or instrument: metrolla = by metro, bussilla = by bus, junalla = by train, autolla = by car, pyörällä = by bike.
Vowel harmony picks -lla here because metro contains the back vowel o. If a word had only front vowels (ä, ö, y), you’d see -llä.
Note: “on foot” is expressed with an adverbial, e.g., kävellen (by walking), not jalalla.

Can I say Menen keskustaan metrolla instead of Menen metrolla keskustaan? Does word order matter?

Both are correct. Finnish word order is flexible with adverbials.
The earlier element tends to be the focus.
- Menen metrolla keskustaan highlights the means (by metro).
- Menen keskustaan metrolla highlights the destination (to downtown).
Neutral speech often places adverbials after the verb; beyond that, use word order to emphasize what matters in context.

What case is keskustaan, and how is it different from keskustassa or keskustasta?

How is keskustaan formed from keskusta?

For many words ending in -a/-ä, the illative is formed by doubling that vowel and adding -n: keskusta → keskustaan.
Other common illative patterns (for reference):
- talo → taloon (double the final vowel),
- huone → huoneeseen (add -eseen to stems ending in -e),
- maa → maahan (add -hVn to long vowel/diphthong stems).

Why isn’t the pronoun minä used? Why just menen?

Finnish verb endings mark the person, so subject pronouns are usually omitted unless emphasized.
Menen already means “I go.” Adding minä is optional and adds emphasis or contrast: Minä menen (as opposed to someone else).

Why is it jään and not jää?

jään is the 1st person singular present of jäädä (to stay/remain): I stay/I will stay.
jää is the 3rd person singular (he/she/it stays).
As with menen, the personal ending -n marks “I.”

Does jäädä mean “to get off” a vehicle here? If I want to say I get off the metro, how do I say it?

jäädä primarily means “to stay/remain; to be left.” In travel it can also mean “to get off,” but that use typically appears with pois and the elative case of the vehicle.
To say “I get off the metro,” use: Jään pois metrosta.
In the given sentence, jään laiturille odottamaan means you remain on the platform to wait (not necessarily the act of alighting from the train).

Why laiturille and not laiturissa or laituriin?

laiturille uses -lle (allative) = onto/to a surface or to a place used with the adessive series.
With “surface/area” nouns like laituri (platform/pier), Finnish uses the adessive trio:
- laiturilla = on/at the platform,
- laiturilta = from/off the platform,
- laiturille = onto/to the platform.
laituriin (illative) would mean “into the platform” (inside its structure), which is not the intended meaning.

What is odottamaan, and why that form?

odottamaan is the illative of the so-called “MA-infinitive” (the -maan/-mään form).
After verbs of movement or change of state (e.g., mennä, tulla, jäädä, lähteä, ruveta), Finnish often uses this form to express purpose or the beginning/continuation of an activity.
So jään … odottamaan ≈ “I stay (in order) to wait” / “I remain to wait.”

How is odottamaan built from odottaa?

Base verb: odottaa (Type 1). Take the stem odotta- and add -maan (back-vowel harmony): odottamaan.
Harmony: front-vowel stems take -mään (e.g., syödä → syömään). Another example: pelata → pelaamaan.

Could I just say Odotan laiturilla instead of Jään laiturille odottamaan?

Odotan laiturilla = I wait on the platform.
Jään laiturille odottamaan adds the nuance that you are staying/remaining there to wait (e.g., you arrive and then stay put).
Both are correct; choose based on whether you want to emphasize the “remaining” part.

Is this talking about the future? There’s no future tense marker.

Finnish has no separate future tense; the present often covers future-time meaning when context makes it clear.
Menen … ja jään … can mean “I’m going … and (then) I’ll stay …” in natural English.

Should there be a comma before ja?

No. Finnish typically does not use a comma before ja when simply coordinating two clauses like this.
A comma might appear with parenthetical inserts or certain subordinate structures, but not here.

Can I say Menen metroon for “I go by metro”?

Menen metroon means “I go into the metro” (i.e., I enter the train/metro system).
To express the means of transport (“by metro”), use the adessive: Menen metrolla.

What’s the difference between keskusta and kaupunki?

keskusta = the city center/downtown area.
kaupunki = the city as a whole.
keskustaan = into downtown; kaupunkiin = into the city (from outside or the general city area).

Any pronunciation tips for this sentence?

Primary stress is always on the first syllable of each word.
Double letters are long: jään (long ä), metrolla (long ll), odottamaan (long tt and long aa), laiturille (long ll).
Keep vowels distinct and long where marked; length differences are meaningful in Finnish.