Learn Hardcore Finnish: Kesällä kaupungissa järjestetään suuri jalkapalloturnaus. - In the summer a big football tournament is organized in the city.

The basic word is kesä = summer.
-llä is the adessive case ending. With times (seasons, holidays, parts of the day), Finnish often uses the adessive to mean “in / during / at”:
- kesällä = in (the) summer
- talvella = in (the) winter
- jouluna = at Christmas
- yöllä = at night

So Kesällä here is “In the summer”, even though there is no separate word for in or the.

Why isn’t it kesässä instead of kesällä?

Kesässä would be the inessive case (“in the inside of summer”), and it sounds wrong for normal time expressions.

For seasons and many other time expressions, Finnish idiomatically uses the adessive (-lla/-llä) instead of the inessive:

kesällä (not kesässä) = in summer
keväällä (not keväässä) = in spring

So kesässä is grammatically possible but would only work in some very strange metaphorical context. In normal speech, only kesällä is correct for “in the summer”.

Why is there no word for “in the” before summer or city?

Finnish usually does not use prepositions or articles the way English does. Instead:

“In” is expressed by a case ending (like -ssa/-ssä or -lla/-llä).
There are no words for “a” or “the” at all.

In the sentence:

Kesällä (kesä + llä) = in (the) summer
kaupungissa (kaupunki + ssa) = in (the) city

So English “in the summer in the city” is expressed by two case endings, with no extra prepositions or articles in Finnish.

What does kaupungissa mean, and why the ending -ssa?

Kaupungissa means “in (the) city”.

The basic word is kaupunki = city.
-ssa/-ssä is the inessive case = “in, inside”.

So:

kaupunki → kaupungissa = in the city
(the -ki changes to -ng before the case ending; this kind of consonant change is normal in Finnish)

Compare:

talossa = in the house (talo + ssa)
autossa = in the car (auto + ssa)

So kaupungissa is the standard way to say “in the city”.

What is the difference between kaupungissa and kaupungilla?

Both are location cases but with different nuances:

kaupungissa (inessive, -ssa): “in the city, inside the city area”
kaupungilla (adessive, -lla): roughly “at the city / by the city”, but this is not usually how you talk about being generally in a city.

For general “in town / in the city”, you normally say kaupungissa.

Kesällä kaupungissa… = In (the) summer, in the city…
Using kaupungilla here would sound wrong or at least unnatural.

What form is järjestetään, and what does it imply?

Järjestetään is the present passive (also often called “impersonal”) form of the verb järjestää (to organize).

järjestää = to organize
järjestetään = “is organized” / “gets organized” / “they organize”

Key points:

There is no explicit subject (no “who”).
It describes what happens rather than who does it.
It often corresponds to English passive (“is organized”) or generic “they organize / people organize”.

So järjestetään here can be understood as:

“a big football tournament is organized”
or “they organize a big football tournament” (every summer, in the city).

Where is the subject in this sentence?

In Finnish passive sentences like this, there is no explicit agent/subject equivalent to English “they / people / the city”.

Instead:

The thing affected by the action (what is organized) is in the nominative case and behaves like the grammatical subject:
- suuri jalkapalloturnaus = the big football tournament (nominative)

So structurally:

Kesällä kaupungissa = adverbials (time, place)
järjestetään = passive verb (“is organized”)
suuri jalkapalloturnaus = subject-like noun phrase (the thing being organized)

The agent (“who organizes it”) is left unspecified and understood from context: the city, the club, people, etc.

Why is it suuri jalkapalloturnaus and not suuren jalkapalloturnauksen?

Suuri jalkapalloturnaus is in the nominative singular, because it functions as the subject-like element of the passive sentence.

suuri = big (adjective, nominative singular)
jalkapalloturnaus = football tournament (noun, nominative singular)

Adjectives agree in case and number with the noun:

suuri turnaus (nominative)
suuren turnauksen (genitive; used e.g. as an object: “Kaupunki järjestää suuren turnauksen.”)

Compare:

Kaupunki järjestää suuren jalkapalloturnauksen.
“The city organizes a big football tournament.”
→ suuren jalkapalloturnauksen is an object in the genitive.
Järjestetään suuri jalkapalloturnaus.
“A big football tournament is organized.”
→ suuri jalkapalloturnaus is in the nominative, acting like a subject.

So the difference in form (suuri vs suuren) is tied to sentence structure (subject vs object).

Why is jalkapalloturnaus one long word instead of three separate words?

Finnish often forms compound words where English would use separate words.

jalka = foot
pallo = ball
jalkapallo = football / soccer
turnaus = tournament
jalkapalloturnaus = football tournament

In Finnish:

The main word (the “head”) is at the end: here, turnaus.
The parts before it narrow the meaning: what kind of tournament? → jalkapalloturnaus.

So you normally write it as one word, not jalkapallo turnaus or jalka pallo turnaus.

Can I change the word order, for example: Suuri jalkapalloturnaus järjestetään kesällä kaupungissa?

Yes. Finnish word order is flexible, and case endings show the roles, not position.

All of these are grammatically correct and mean roughly the same thing:

Kesällä kaupungissa järjestetään suuri jalkapalloturnaus.
→ Emphasis starts from “In the summer, in the city”.
Kaupungissa kesällä järjestetään suuri jalkapalloturnaus.
→ Similar, maybe slightly stronger focus on place first.
Suuri jalkapalloturnaus järjestetään kesällä kaupungissa.
→ Starts by introducing the tournament.

Changing word order mostly changes emphasis / what is presented as “old vs new information”, not the basic meaning. The given sentence highlights the time and place first.

How would I say “The city organizes a big football tournament in the summer” with an explicit subject?

You would use an active sentence instead of the passive:

Kaupunki järjestää kesällä suuren jalkapalloturnauksen.

Breakdown:

Kaupunki = the city (subject)
järjestää = organizes (3rd person singular)
kesällä = in (the) summer
suuren jalkapalloturnauksen = a big football tournament (object, genitive singular)

Compare that with the original passive:

Kesällä kaupungissa järjestetään suuri jalkapalloturnaus.
→ In the summer, in the city, a big football tournament is organized. (no explicit “the city” as subject)