Learn Hardcore Finnish: Kengät jäävät aina eteiseen, jotta lattia pysyy puhtaana. - The shoes always stay in the hallway so that the floor stays clean.

In Finnish, the basic subject form in the plural usually ends in -t (and often the stem changes a bit). Because the verb jäävät is plural, the subject must also be plural: kengät jäävät = the shoes stay / are left.

What does jäävät mean, and why is it used instead of something like ovat?

Jäävät is the 3rd person plural present tense of jäädä.

jäädä = to stay, to remain, to be left (behind)
jäävät = (they) stay / remain / are left

Here, kengät jäävät aina eteiseen literally means the shoes always remain in / end up in the hallway.

Using olla (ovat) would just say the shoes are in the hallway (a static description), while jäädä emphasizes that they are left there and don’t go further inside.

Why is it eteiseen and not eteinen or eteisessä?

The base form is eteinen (hallway, entrance).

Eteiseen is the illative case, which often means “into” or “to (inside)” a place.

eteinen = hallway (dictionary form)
eteisessä = in the hallway (inside, static; inessive case)
eteiseen = into the hallway (movement or end point of movement; illative case)

With verbs like jäädä, Finnish often uses the illative to mark the place where something ends up / is left. So jäädä + illative = to stay / remain in(to) a place:
kengät jäävät eteiseen = the shoes stay (end up) in the hallway.

Does eteiseen mean “into the hallway” (movement) or “in the hallway” (location)?

Grammatically it’s the illative, which is a “movement into” case (into the hallway).

But with jäädä, the focus is not on a dynamic motion like walking into, but on the resulting location: where the shoes are left / remain.

So you can think of it as:

literal: the shoes remain into the hallway
natural English: the shoes stay in the hallway / are left in the hallway

Finnish uses the illative here because the hallway is the end point where the shoes are left.

What does jotta mean, and how is it different from että or koska?

Jotta usually means “so that / in order that” and introduces a purpose or intended result.

Kengät jäävät aina eteiseen, jotta lattia pysyy puhtaana.
→ The shoes always stay in the hallway, so that the floor stays clean.

Differences:

jotta: purpose or goal
- Teen tämän, jotta sinä voit levätä.
  I’ll do this so that you can rest.
että: more neutral “that”, for content clauses or reported speech
- Tiedän, että sinä tulet.
  I know that you’re coming.
koska: cause/reason (“because”)
- Teen tämän, koska sinä olet väsynyt.
  I’m doing this because you are tired.

In this sentence, the hallway rule is for the purpose of keeping the floor clean, so jotta is natural.

Why is there a comma before jotta?

In Finnish, subordinate clauses (like purpose clauses with jotta) are usually separated from the main clause with a comma.

Main clause: Kengät jäävät aina eteiseen
Subordinate clause: jotta lattia pysyy puhtaana

So a comma before jotta is the standard punctuation rule: main clause, then comma, then the jotta-clause.

Why is it pysyy and not a conditional form like pysyisi after jotta?

Pysyy is the 3rd person singular present tense of pysyä (“to stay, remain”).

Many grammar books say jotta often goes with the conditional (e.g. pysyisi) in true purpose sentences:

Teen näin, jotta lattia pysyisi puhtaana.
I do this so that the floor would stay clean.

But in everyday Finnish, it’s common and fully acceptable to use the indicative (pysyy) after jotta, especially when:

the result is seen as regular / factual, not hypothetical
you talk about a habit or rule

So here:

Kengät jäävät aina eteiseen, jotta lattia pysyy puhtaana.
describes a regular practice and its regular result.

What case is puhtaana, and why not just puhdas or puhtaaksi?

Puhtaana is the essive case of puhdas (clean).

puhdas = clean (dictionary form)
puhtaana = “as clean / in a clean state” (essive)

The structure pysyä + adjective in essive means “to stay/remain in a certain state”:

pysyä terveenä = to stay healthy
pysyä rauhallisena = to remain calm
pysyä puhtaana = to stay clean

So lattia pysyy puhtaana literally: the floor stays as clean / in a clean state.

Puhtaaksi would be the translative (into a clean state), more like “to become clean” or “to get clean” – that would change the meaning.

Why is lattia in the basic form and not in some special case?

Lattia (floor) here is in the nominative singular, because it is the subject of the verb pysyy:

lattia = subject
pysyy = verb
puhtaana = predicate in essive (describing the state of the subject)

So structurally:
(The) floor stays clean → Lattia pysyy puhtaana.

No special case is needed for the subject in this simple clause.

Can I change the word order, e.g. put the jotta-clause first?

Yes. Finnish word order is flexible. For example:

Jotta lattia pysyy puhtaana, kengät jäävät aina eteiseen.

This is correct and natural. It slightly emphasizes the purpose (keeping the floor clean) by mentioning it first.

The meaning is the same; it’s more a question of what you want to highlight first.

Can I say Kengät aina jäävät eteiseen instead of Kengät jäävät aina eteiseen?

You can, and it is grammatical, but the emphasis changes.

Kengät jäävät aina eteiseen
→ neutral, aina (always) modifies jäävät in a normal, unmarked position.
Kengät aina jäävät eteiseen
→ puts a bit more emphasis on “always”, almost like:
The shoes always (and I mean always) stay in the hallway.

So it’s possible, but the original is the most neutral, everyday word order.

Why are the shoes plural (kengät), but the hallway is singular (eteiseen)?

In Finnish (and in English), a plural subject can go to a singular location:

many shoes → one hallway

The number of the subject (kengät) does not force the place word (eteinen) to be plural.

So kengät jäävät eteiseen = the shoes stay in the hallway is perfectly normal: multiple items in a single place. You would only make the place plural (eteisiin) if there were multiple separate hallways involved.