Vanha leluauto toimii vielä, vaikka sillä on leikitty paljon.

Because Finnish usually writes compound nouns as a single word.

• lelu = toy
• auto = car
• leluauto = toy car

This is very common in Finnish. The last part is the main noun, so a leluauto is a kind of auto.

Because vanha leluauto is the subject of the sentence, so it is in the nominative form.

• vanha = old
• leluauto = toy car

Finnish adjectives usually agree with the noun they describe, so both stay in the basic nominative form here:

• vanha leluauto toimii = the old toy car works

If the noun were in another case, the adjective would usually change too:

• vanhan leluauton = of the old toy car / the old toy car as an object in some contexts

toimii comes from toimia, which means to work, to function, or to operate.

So:

• toimii = works / functions
• vielä = still

Together, toimii vielä means still works or still functions.

The word vielä adds the idea that this is perhaps a little surprising: despite age or heavy use, it continues to work.

Vaikka means although, even though, or though.

It introduces a clause that contrasts with the main statement:

• Vanha leluauto toimii vielä = The old toy car still works
• vaikka sillä on leikitty paljon = even though it has been played with a lot

So vaikka marks a concessive idea: something is true despite another fact.

Because vaikka introduces a subordinate clause, and in Finnish subordinate clauses are normally separated by a comma.

So the structure is:

• main clause: Vanha leluauto toimii vielä
• subordinate clause: vaikka sillä on leikitty paljon

That comma is standard Finnish punctuation.

Sillä is the adessive form of se.

• se = it
• sillä = with it / on it / using it, depending on context

Here it refers back to leluauto.

The important point is that the verb leikkiä often uses the adessive case when talking about the toy or thing someone plays with:

• leikkiä autolla = to play with a car
• leikkiä sillä = to play with it

So sillä is not random; it is the form the verb naturally calls for here.

Because in this meaning, leikkiä does not normally take a direct object.

With toys or objects, Finnish usually says:

• leikkiä jollakin = play with something

So:

• sillä on leikitty = people have played with it

Using sitä would sound wrong here for most learners’ intended meaning.

A useful comparison:

• leikkiä pallolla = play with a ball
• leikkiä nukella = play with a doll
• leikkiä leluhansikkaalla etc.

So this is something you often just have to learn with the verb.

It is the perfect passive (more precisely, the Finnish impersonal passive in the perfect tense) of leikkiä.

Breakdown:

• on = has / have
• leikitty = played

Together, on leikitty means something like:

• has been played
• more naturally in English here: people have played / it has been played with

Finnish uses this passive/impersonal form very often when the doer is unknown, unimportant, or meant in a general sense.

So sillä on leikitty paljon means:

• it has been played with a lot
• literally closer to: with it has been played a lot

Because Finnish often uses the passive/impersonal to leave the doer unspecified.

In English, we might say:

• It has been played with a lot
• People have played with it a lot
• The kids have played with it a lot

Finnish chooses the passive here because the exact people do not matter. The important point is simply that the toy car has seen a lot of use.

Paljon means a lot or much.

Here it functions as an adverb, modifying the whole verb phrase:

• sillä on leikitty paljon = it has been played with a lot

So paljon tells us the degree or amount of playing.

That is a very natural place for it in Finnish.

The clause:

• sillä on leikitty paljon

has a neutral, normal flow:

• sillä = with it
• on leikitty = has been played
• paljon = a lot

Putting paljon at the end gives it a natural focus. Finnish word order is flexible, but this version sounds standard and smooth.

Yes. For example:

• Vanha leluauto toimii vielä, vaikka lapset ovat leikkineet sillä paljon.

That means:

• The old toy car still works, even though the children have played with it a lot.

This version names the doer: lapset = the children.

The original sentence is more general and a bit more idiomatic if the speaker does not care who exactly did the playing.

Yes. It comes from the verb leikkiä and uses the passive marker -ttu/-tty, which is common in Finnish passive forms.

So very roughly:

• dictionary form: leikkiä
• passive participle form used here: leikitty

You do not need to predict every form perfectly at first, but it is useful to recognize that -ttu/-tty often points to a passive result/form in Finnish.

It has two parts:

1. Vanha leluauto toimii vielä
   = main clause

2. vaikka sillä on leikitty paljon
   = subordinate concessive clause

So the pattern is:

• [main statement] + vaikka + [contrasting fact]

In natural English terms:

• The old toy car still works, even though it has been played with a lot.

That is a very typical Finnish sentence pattern.