Learn Hardcore Finnish: Ennen joulua kauppa on ruuhkainen. - Before Christmas the store is crowded.

You cannot say ennen joulu in standard Finnish, and ennen joulun is not normal either (you would rather say joulun alla = “just before Christmas / in the run-up to Christmas”).

So joulua is there because the preposition ennen requires the partitive case.

What exactly does ennen joulua do in the sentence, and can it move to another position?

Ennen joulua is a time adverbial, telling when the shop is busy.

In Finnish, time expressions can move quite freely:

Ennen joulua kauppa on ruuhkainen.
Kauppa on ruuhkainen ennen joulua.

Both are grammatically correct and mean the same thing. The difference is in emphasis / information structure:

Ennen joulua kauppa on ruuhkainen.
→ Emphasis on the time before Christmas; that time is being contrasted with other times.
Kauppa on ruuhkainen ennen joulua.
→ More neutral; starts with the topic kauppa (the shop).

You could also say:

Joulua ennen kauppa on ruuhkainen.

Here ennen is used as a postposition; the meaning and case (partitive joulua) are the same.

Why is kauppa in its basic form and not something like kaupan?

Kauppa is the subject of the sentence, so it appears in the nominative singular (basic form).

kauppa = shop, store (subject here)
on = is
ruuhkainen = busy, crowded (predicative adjective describing the subject)

If you changed it to kaupan, that would normally be the genitive form, meaning “of the shop” or “the shop’s”, and it would no longer function as a simple subject:

kaupan ovi = the shop’s door
kaupan edessä = in front of the shop

So in this sentence, to say “the shop is busy”, you need kauppa in the nominative as the subject.

Why is it ruuhkainen and not something like ruuhkaista or ruuhkaisena?

Ruuhkainen is an adjective meaning busy, crowded, congested (from the noun ruuhka, “traffic jam / rush / crowd”). In this sentence it’s used as a predicative adjective after the verb olla (“to be”).

With a singular, affirmative sentence like this, the basic rule is:

Subject in nominative
Predicative adjective also in nominative, matching the subject

So we get:

kauppa (subject, nominative singular)
on (verb)
ruuhkainen (predicative adjective, nominative singular)

Other forms you mentioned:

ruuhkaista = partitive form, used in some special contexts to emphasize partialness, incompleteness, or in certain negative structures (more advanced nuance).
ruuhkaisena = essive case, meaning “when (it is) busy / in a busy state”. For example:
- Kauppa on jouluna ruuhkaisena koko päivän.
  = The shop is in a busy state all day at Christmas. (less common way to phrase it)

For a simple description “The shop is busy”, ruuhkainen (nominative) is the normal choice.

Does kauppa here mean “a shop” or “the shop”? How do you know, since Finnish has no articles?

Finnish does not use articles like a or the, so kauppa can correspond to either “a shop” or “the shop” depending on context.

Possible readings:

a shop / shops in general
- As a general statement about what shops are like before Christmas (often understood contextually):
  - “Before Christmas, a shop is busy.”
  - More naturally in English: “Shops are busy before Christmas.”
the shop (a specific one already known from context)
- Maybe you and your friend have been talking about one particular shop:
  - “You know that shop near my house? Before Christmas, the shop is busy.”

To force a more clearly specific meaning, Finnish can use demonstratives:

se kauppa = that (specific) shop
tämä kauppa = this shop

But in many everyday contexts, a plain kauppa is interpreted as the relevant shop everyone knows from the situation.

Can I say Jouluna kauppa on ruuhkainen instead of Ennen joulua? What’s the difference?

Yes, you can, but the meaning changes slightly because you change the time expression and the case of joulu:

Ennen joulua kauppa on ruuhkainen.
- ennen + partitive (joulua)
- Meaning: before Christmas, in the time leading up to it.
Jouluna kauppa on ruuhkainen.
- jouluna = essive case of joulu
- Meaning: at Christmas / on Christmas (on the holiday or during the festive days).

So:

ennen joulua = “in the run-up to Christmas, before Christmas day(s)”
jouluna = “during Christmas (time itself)”

Both structures are common; they just refer to different parts of the season.

Can ennen come after joulu instead of before it?

Yes. Ennen can be used both as a preposition (before the noun) and as a postposition (after the noun), and it still requires the partitive:

ennen joulua
joulua ennen

Both mean “before Christmas”.

Examples:

Ennen joulua kauppa on ruuhkainen.
Joulua ennen kauppa on ruuhkainen.

The difference is mostly stylistic and about rhythm and emphasis; both are grammatically correct and natural.

How would I say “Shops are busy before Christmas” in Finnish?

You need the plural forms of kauppa and ruuhkainen:

Ennen joulua kaupat ovat ruuhkaisia.

Breakdown:

kaupat = shops (nominative plural of kauppa)
ovat = are (3rd person plural of olla)
ruuhkaisia = busy, crowded (partitive plural of ruuhkainen)

You can also use the more neutral word order:

Kaupat ovat ruuhkaisia ennen joulua.

How would I turn this into a yes–no question: “Is the shop busy before Christmas?”

In Finnish yes–no questions, you usually add the -ko / -kö ending to the verb and keep almost the same word order:

Onko kauppa ruuhkainen ennen joulua?
= Is the shop busy before Christmas?

Structure:

on → onko (question form of the verb olla)
kauppa = the shop (subject)
ruuhkainen = busy (predicative)
ennen joulua = before Christmas (time adverbial)

You can still move the time expression if you want to emphasize it:

Ennen joulua, onko kauppa ruuhkainen? (spoken, slightly more emphatic on the time)

What exactly does ruuhkainen mean? Is it just “busy” like in “I’m busy”, or more like “crowded”?

Ruuhkainen is based on ruuhka, which means traffic jam, rush, crowding, congestion. So ruuhkainen describes something that is:

crowded with people
jammed / congested
very busy in the sense of full of customers / traffic

So in this sentence:

Ennen joulua kauppa on ruuhkainen.
→ “Before Christmas, the shop is crowded / very busy (full of customers).”

For “I’m busy (with work, tasks)”, Finnish usually uses other expressions, e.g.:

Minulla on paljon tekemistä. = I have a lot to do.
Olen kiireinen. = I am busy (have a lot going on).

So ruuhkainen is primarily about crowds and congestion, not about a person’s schedule.