Pysäköinninvalvoja voi todentaa pysäköintivirheen todistusaineistosta.

Because it is a Finnish compound noun. Finnish very often combines words into a single word where English would use several words.

Here, the parts are:

• pysäköinnin = of parking / parking-related
• valvoja = supervisor, inspector, monitor

So pysäköinninvalvoja means a person who supervises parking, in practice a parking inspector / parking enforcement officer.

This does not mean literal possession, as if the supervisor belonged to parking. In compounds, Finnish often uses a genitive-looking first part just to show a relationship.

That form is the genitive singular of pysäköinti.

The noun changes like this:

• pysäköinti = parking
• pysäköinnin = of parking

This is a normal pattern for many nouns ending in -nti / -nti-type forms: the stem changes and you get -nnin in the genitive.

In this sentence, pysäköinnin- is used as the first part of the compound pysäköinninvalvoja.

So you can think of it as:

• pysäköinnin valvoja = supervisor of parking
• then written together as pysäköinninvalvoja

This is a very common Finnish verb structure:

• voi = 3rd person singular present of voida = can / may
• todentaa = the first infinitive = to verify / to establish

So voi todentaa means can verify or is able to verify.

After voida, the main verb stays in the infinitive:

• voin tulla = I can come
• voit nähdä = you can see
• voi todentaa = can verify

Because it is the object of the verb, and in this kind of sentence Finnish often uses the total object in the singular, which usually looks like the genitive.

The base noun is:

• pysäköintivirhe = parking violation / parking error

As the total object, it becomes:

• pysäköintivirheen

Here the idea is that the inspector can verify the whole specific violation, not just some unspecified amount of violation.

So the -n here is not showing possession. It is functioning as the object form.

A useful rough contrast is:

• total object: the action is directed at a complete, specific thing
• partitive object: the action is incomplete, ongoing, negative, or directed at an unspecified amount

Yes. It is another compound:

• pysäköinti = parking
• virhe = mistake, error, violation

So pysäköintivirhe literally means something like parking error, but in context it is better understood as a parking violation.

Finnish often builds official and administrative vocabulary this way, by combining nouns into compact compounds.

It is in the elative case, marked by -sta / -stä.

The base form is:

• todistusaineisto = evidence, evidentiary material

The elative form is:

• todistusaineistosta = from the evidence, out of the evidence, or more naturally on the basis of the evidence

In this sentence, it tells the source or basis from which the parking violation can be verified.

So the idea is:

• the inspector can verify the violation
• from / on the basis of the evidence

Because the sentence is focusing on the source of the verification, not just the location of something.

The elative -sta / -stä often means:

• from
• out of
• on the basis of

So todistusaineistosta suggests that the violation can be established from the evidence available.

If Finnish wanted to emphasize being literally in something, another case might be used, but here the meaning is closer to derived from or based on.

Yes. Finnish word order is more flexible than English because the case endings show the grammatical roles.

This sentence has a fairly neutral order:

• Pysäköinninvalvoja = subject
• voi todentaa = verb phrase
• pysäköintivirheen = object
• todistusaineistosta = source/basis phrase

But you could move parts around for emphasis. For example:

• Todistusaineistosta pysäköinninvalvoja voi todentaa pysäköintivirheen.

That would emphasize the evidence more strongly.

Even when the order changes, the case endings help you see what each word is doing.

Because Finnish has no articles.

So Finnish does not have separate words matching English a/an and the. Whether something is definite or indefinite is understood from context.

That means pysäköinninvalvoja can mean:

• a parking inspector
• the parking inspector

and pysäköintivirheen can mean:

• a parking violation
• the parking violation

The exact English choice depends on the context, not on a separate article in Finnish.

This is a good vocabulary question, because both can relate to proving something, but they are not always identical.

• todentaa often means to verify, to establish as true, to confirm, especially in formal or technical contexts
• todistaa often means to prove, and it can also mean to testify or to bear witness

In this sentence, todentaa sounds appropriate because the idea is that the inspector can verify / establish the parking violation from the evidence.

So todentaa fits an official, evidence-based statement very well.