Nigdzie nie mogę znaleźć mojej skórzanej torebki.

Yes, it is a kind of double negative by English standards, but in Polish this is normal and required. Polish uses negative concord, which means that if the sentence is negative, the other negative words also stay negative.

So:

• nigdzie = nowhere
• nie mogę = I cannot

Together:

• Nigdzie nie mogę znaleźć... = I can’t find ... anywhere / nowhere can I find ...

In standard Polish, you normally must keep nie with the verb:

• Nigdy nie... = never
• Nikt nie... = nobody
• Nic nie... = nothing
• Nigdzie nie... = nowhere

So Nigdzie mogę znaleźć... would be incorrect.

Because the noun phrase is not in the nominative form here. It changes case.

The dictionary form is:

• moja skórzana torebka = my leather handbag
  (nominative singular)

But in this sentence, the object comes after a negated verb (nie mogę znaleźć), and in Polish that very often makes the direct object go into the genitive.

So:

• moja skórzana torebka → nominative
• moją skórzaną torebkę → accusative
• mojej skórzanej torebki → genitive

Because the sentence is negative, Polish uses:

• Nigdzie nie mogę znaleźć mojej skórzanej torebki.

Without negation, you would normally say:

• Mogę znaleźć moją skórzaną torebkę.

It is mainly because of the negation.

The verb znaleźć normally takes a direct object in the accusative:

• Znalazłem moją torebkę. = I found my handbag.

But when the verb is negated, Polish often changes that object to the genitive:

• Nie znalazłem mojej torebki. = I didn’t find my handbag.

So in your sentence:

• nie mogę znaleźć triggers the genitive object
• therefore mojej skórzanej torebki

This is a very important Polish pattern.

This is a modal-style construction:

• mogę = I can / I am able to
• znaleźć = infinitive, to find

So literally:

• nie mogę znaleźć = I cannot find

This works like English can + infinitive:

• I can find
• I can’t find

In Polish:

• mogę znaleźć
• nie mogę znaleźć

The first verb (mogę) is conjugated, while the second verb (znaleźć) stays in the infinitive.

Because these verbs do not mean exactly the same thing.

• znaleźć = to find (perfective)
• znajdować = imperfective partner of znaleźć, often to be finding / to find repeatedly / to locate
• szukać = to look for

Your sentence means not just that the speaker is searching, but that they cannot succeed in finding the bag. That is why znaleźć is natural here.

Compare:

• Nie mogę znaleźć torebki. = I can’t find the bag.
• Szukam torebki. = I’m looking for the bag.

So szukać focuses on the search, while znaleźć focuses on the result.

Literally, nigdzie means nowhere.

But in English, negative sentences often use anywhere instead of nowhere in natural translation:

• Nigdzie nie mogę znaleźć...
• literally: Nowhere I cannot find...
• natural English: I can’t find ... anywhere.

So depending on how you translate it, nigdzie may correspond to:

• nowhere
• anywhere in a negative sentence

That is a translation issue, not a grammar problem in Polish.

Yes, that is also natural.

Polish word order is more flexible than English, and the meaning stays basically the same. These are all possible:

• Nigdzie nie mogę znaleźć mojej skórzanej torebki.
• Nie mogę nigdzie znaleźć mojej skórzanej torebki.
• Mojej skórzanej torebki nigdzie nie mogę znaleźć.

The differences are mainly about emphasis.

• Starting with nigdzie emphasizes nowhere / anywhere
• Starting with nie mogę emphasizes I can’t
• Starting with mojej skórzanej torebki emphasizes the handbag itself

So the original sentence sounds very natural and puts early focus on nowhere / anywhere.

Because Polish often drops subject pronouns when they are not needed.

The verb form mogę already tells you the subject is I:

• mogę = I can
• możesz = you can
• może = he/she/it can

So ja is unnecessary unless you want extra emphasis or contrast.

Compare:

• Nie mogę znaleźć torebki. = normal
• Ja nie mogę znaleźć torebki. = I can’t find the bag (maybe someone else can)

This is called pro-drop, and it is very common in Polish.

The base form is torebka.

Here are the relevant forms:

• torebka = nominative singular
• torebkę = accusative singular
• torebki = genitive singular

In this sentence, you see torebki because the noun is in the genitive singular after negation.

Also, torebka usually means:

• handbag
• small bag
• sometimes purse, depending on context

With skórzana (leather), the meaning leather handbag is very natural.

Because adjectives and adjective-like words in Polish must agree with the noun they describe.

Here:

• mojej = my
• skórzanej = leather
• torebki = handbag

All three are:

• feminine
• singular
• genitive

So they all match.

This is called agreement.

You can compare:

Nominative:

• moja skórzana torebka

Accusative:

• moją skórzaną torebkę

Genitive:

• mojej skórzanej torebki

The endings change together.

Yes. The biggest change would be the case of the object.

Negative:

• Nigdzie nie mogę znaleźć mojej skórzanej torebki.

Positive:

• Mogę znaleźć moją skórzaną torebkę.

Notice:

• mojej skórzanej torebki = genitive
• moją skórzaną torebkę = accusative

So one very useful thing to learn from this sentence is:

• positive transitive verb → often accusative object
• negated transitive verb → often genitive object

A very everyday version would be:

• Nie mogę nigdzie znaleźć mojej skórzanej torebki.

This may feel a bit closer to English word order:

• I can’t find my leather handbag anywhere.

But the original:

• Nigdzie nie mogę znaleźć mojej skórzanej torebki

is also completely natural. It just puts nigdzie first for emphasis.

Yes, skórzany / skórzana / skórzane is the normal adjective meaning made of leather.

Because torebka is feminine singular, you get:

• skórzana torebka = leather handbag

And in this sentence, because of the genitive:

• skórzanej torebki

So the adjective changes form to match the noun, but the basic meaning stays the same: leather.