Järven jää on talvella niin paksu, että siellä voi kävellä.

The lake’s ice is so thick in winter that you can walk there.

Breakdown of Järven jää on talvella niin paksu, että siellä voi kävellä.

• olla: to be
• kävellä: to walk
• voida: can
• -lla: in
• siellä: there
• talvi: the winter
• että: that
• järvi: the lake
• niin: so
• paksu: thick
• jää: the ice

Questions & Answers about Järven jää on talvella niin paksu, että siellä voi kävellä.

Why is järven in the genitive case instead of järvi?

Järven is the genitive singular of järvi (“lake”). In Finnish, the genitive is used to show possession or a close belonging-relationship, similar to English “the lake’s ice”.

• järvi = lake (basic form, nominative)
• järven = of the lake / the lake’s (genitive)
• jää = ice (the thing that belongs to the lake here)

So järven jää literally means “the lake’s ice”, just like koiran häntä = “the dog’s tail”.

Why is jää in the basic form (nominative) and not something like jään?

Jää is the subject of the verb on (“is”), so it stays in the nominative case.

The pattern is:

• Järven jää on… = “The lake’s ice is…”

Only the possessor (järvi) takes the genitive form (järven). The thing being described (jää) is the actual subject and stays nominative:

• Järven jää on paksu. = “The lake’s ice is thick.”

Why does talvella mean “in winter”? Why the ending -lla?

Talvella is the adessive case of talvi (“winter”):

• talvi = winter (basic form)
• talvella = in (the) winter / during winter

The adessive -lla/-llä often expresses:

• location: “on/at” something (e.g. pöydällä = on the table)
• time: “in/during/at” a time period (e.g. kesällä = in summer, yöllä = at night)

So talvella is a very standard way to say “in winter” or “during the winter”.

Could the word order be different, like Talvella järven jää on niin paksu…?

Yes. Finnish word order is flexible. These are all correct:

• Järven jää on talvella niin paksu, että…
• Talvella järven jää on niin paksu, että…
• Järven jää on niin paksu talvella, että… (slightly marked/emphatic)

The basic meaning stays the same. Changing word order mainly shifts emphasis:

• Starting with Talvella… emphasizes the time: “In winter, the lake’s ice is so thick…”
• The original order is more neutral: “The lake’s ice is, in winter, so thick that…”

How does the niin paksu, että structure work? Is it like “so thick that”?

Exactly. Niin … että is a common result construction in Finnish:

• niin paksu, että = so thick that
• niin korkea, että = so tall that
• niin kylmä, että = so cold that

Structure:

1. niin
   • adjective: niin paksu
2. Comma
3. että
   • result clause: että siellä voi kävellä

So the sentence literally follows the English pattern:

• “The lake’s ice is in winter so thick that you can walk there.”

What is että doing here? Is it like English “that”, and why is there a comma before it?

Here että is a conjunction introducing a result clause, very close to English “that” in “so X that…”.

• niin paksu, että siellä voi kävellä
  = “so thick that you can walk there”

In Finnish, a comma is normally written before että when it starts a new clause. So:

• main clause: Järven jää on talvella niin paksu
• comma
• subordinate/result clause: että siellä voi kävellä

What does siellä refer to exactly? Why not siinä or tuolla?

Siellä is a place adverb meaning roughly “there (in that place)”. In this sentence, it refers back to the location implied by järven jää – the surface of the lake’s ice.

Rough contrasts:

• siellä = there (in/at that place), more general
• siinä = in/on that specific thing, more tightly tied to a concrete object just mentioned
• tuolla = over there (often something visible or indicated by pointing)

Siellä is very natural here because we’re talking about “there, on that ice (as a place where you can be)”, not pointing at a specific visible spot or object. You could also say jäällä voi kävellä (“you can walk on the ice”), but siellä keeps it nicely tied to the previous clause without repeating jää.

Why is the verb voi in 3rd person singular if it means “you/people can walk there”?

The verb voi is 3rd person singular of voida (“can, to be able to”):

• (hän) voi = he/she/it can

Finnish often omits an explicit subject when talking about general possibility or “people in general”. The structure voi + infinitive can mean:

• “one can …”
• “people can …”
• “you can …” (generic you)

So:

• siellä voi kävellä
  literally: “there can walk”
  naturally: “you can walk there” / “it’s possible to walk there”

No pronoun is needed; the generic meaning is understood from context.

Why is kävellä in the basic infinitive form and not kävelee?

After voi (“can”), Finnish uses the first infinitive (basic dictionary form) of the main verb:

• voi kävellä = can walk
• voi syödä = can eat
• voi nukkua = can sleep

If you said siellä kävelee, that would mean “(someone) walks there / (someone) is walking there”, a normal finite verb form.

With modal meaning (“can, may, must, want to”), use:

• voida + infinitive: voi kävellä
• haluta + infinitive: haluan kävellä (I want to walk)
• etc.

Could I say että jäällä voi kävellä instead of että siellä voi kävellä? What’s the difference?

Yes, you can say:

• Järven jää on talvella niin paksu, että jäällä voi kävellä.

Here jäällä = “on the ice” (adessive case of jää).

Differences:

• siellä voi kävellä = “you can walk there”, referring back to the place already established (the ice on the lake).
• jäällä voi kävellä = explicitly repeats the location “on the ice”.

Both are correct. Siellä is a bit more fluent and avoids repetition; jäällä is more explicit about the physical surface you walk on.

Why are there no articles like “the” or “a” in järven jää or talvella?

Finnish has no articles (a/an, the). Definiteness and specificity are understood from context, word order, and case endings.

• järven jää can mean “the lake’s ice” or, in another context, just “(some) lake’s ice”.
• talvella is understood as “in (the) winter” because that makes sense contextually.

Learners have to supply a/the mentally when translating into English. Finnish simply doesn’t mark this grammatically.

Could I say Järven jää on niin paksu talvella, että siellä voi kävellä? Does moving talvella change the meaning?

Yes, that version is also correct:

• Järven jää on niin paksu talvella, että siellä voi kävellä.

Meaning is essentially the same. The subtle difference is in rhythm and emphasis:

• on talvella niin paksu: slight emphasis on “in winter” as a setting.
• on niin paksu talvella: slight emphasis on “so thick (in winter)”, as if contrasting with another time.

In normal conversation, they are interchangeable; context matters more than this small word order change.