En löydä niitä missään.

Because en already shows the person.

In Finnish, negation uses a special negative verb, and that verb is conjugated for person:

• en = I do not
• et = you do not
• ei = he/she/it does not
• emme = we do not
• ette = you (plural) do not
• eivät = they do not

So En löydä... already means I don’t find... / I can’t find....

You can add minä:

• Minä en löydä niitä missään.

But that usually adds emphasis, contrast, or clarity. In normal Finnish, the pronoun is often omitted when it is obvious.

Because in Finnish negative sentences, the negative verb is the part that gets conjugated, not the main verb.

Compare:

• löydän = I find
• en löydä = I do not find

So the pattern is:

• affirmative: personal ending on the main verb
• negative: personal ending on the negative verb, and the main verb appears in a special short form

Here:

• dictionary form: löytää = to find
• affirmative 1st person singular: löydän = I find
• negative 1st person singular: en löydä = I don’t find

You may also notice the stem change löytää → löyd- in many forms. That is normal for this verb.

The dictionary form is löytää, meaning to find.

The form löydä is not the dictionary form by itself. It is the form used after the negative verb in the present tense:

• löytää = to find
• löydän = I find
• en löydä = I do not find

So if you look this up in a dictionary, search for löytää, not löydä.

Because Finnish usually uses the partitive object in negative sentences.

Compare:

• Löydän ne. = I find them.
• En löydä niitä. = I don’t find them.

So:

• ne = nominative plural / total object type
• niitä = partitive plural

Negation is one of the most common reasons Finnish switches the object into the partitive.

This is a very important pattern in Finnish:

• Ostan kirjan. = I buy the book.
• En osta kirjaa. = I’m not buying the book.

Likewise:

• Löydän ne.
• En löydä niitä.

In this sentence, missään means anywhere.

It belongs to a set of forms related to mikään and is used in negative contexts. In practice, you can think of it as the Finnish word used for anywhere after negation.

A useful comparison:

• missä? = where?
• missään = anywhere / nowhere in a negative sentence
• mistään = from anywhere

So:

• En löydä niitä missään. = I can’t find them anywhere.

Literally, the Finnish structure is closer to I don’t find them anywhere / nowhere, but natural English usually says I can’t find them anywhere.

No—not in the English sense.

Finnish normally combines a negative verb with words like:

• kukaan = anyone
• mikään = anything
• missään = anywhere
• koskaan = ever

So a sentence like:

• En löydä niitä missään

is completely normal Finnish. It does not cancel itself out into a positive meaning.

English learners sometimes feel it looks like a double negative, but in Finnish this is just standard grammar.

Because that is usually the most natural English translation.

Finnish en löydä is simply the present negative of löytää, so word-for-word it is I do not find. But in a situation where someone is searching and not succeeding, English usually says:

• I can’t find them anywhere.

So the Finnish sentence does not need a separate word meaning can in order to express that natural idea.

If you said En voi löytää niitä, that would sound more like I am not able to find them or I cannot possibly find them, which is a different nuance.

Usually, in standard Finnish, niitä here most naturally refers to things.

For people, standard Finnish would more often use heitä as the partitive plural object:

• En löydä heitä missään. = I can’t find them anywhere.
  (when them = people)

However, in everyday spoken Finnish, ne / niitä are often used for people too. So in colloquial speech you may hear:

• En löydä niitä missään.

even when the speaker means people.

So the answer is:

• standard written Finnish: usually things
• spoken Finnish: can also mean people

Yes. Finnish word order is fairly flexible, and changing it changes the emphasis.

The sentence you have is a neutral, natural order:

• En löydä niitä missään.

But you could also say:

• Niitä en löydä missään.
  This emphasizes them.

• Missään en löydä niitä.
  This emphasizes anywhere.

The meaning stays close, but the focus changes.

So Finnish word order is not as rigid as English word order. Learners should pay attention not only to what form is used, but also to what is being emphasized.

Because missään expresses location: in/at anywhere.

A simple way to remember the difference:

• missä = where?
• missään = anywhere
• mistä = from where?
• mistään = from anywhere

With löytää, when you mean find somewhere / not find anywhere, Finnish normally uses the location idea:

• En löydä niitä missään.

If you used mistään, the meaning would shift toward from anywhere or out of anywhere, which is not what this sentence is doing.

So:

• missään = correct here
• mistään = different case, different meaning