Nigde ne vidim torbu.

Yes, from an English point of view it looks like a double negative, but in Serbian this is normal and required. Serbian uses negative concord, which means multiple negative elements appear together in the same sentence.

So:

• nigde = nowhere
• ne vidim = I do not see

Together: Nigde ne vidim torbu.

You generally cannot say Nigde vidim torbu without ne. The verb must also be negated.

Nigde means nowhere.

It is built from the same family as words like:

• gde = where
• negde = somewhere
• svugde / svuda = everywhere
• nigde = nowhere

In negative sentences, nigde often corresponds to English nowhere or anywhere depending on how the English sentence is phrased.

So although English might say I can’t see the bag anywhere, Serbian naturally says Nowhere I don’t see the bag, using negative concord.

Because torbu is the accusative singular form of torba.

• torba = nominative singular, the dictionary form
• torbu = accusative singular

Here, torba is the direct object of the verb vidim (I see), so it must be in the accusative.

For feminine nouns ending in -a, the accusative singular usually changes to -u:

• knjiga → knjigu
• žena → ženu
• torba → torbu

No. In this sentence, the object still stays in the accusative:

• Vidim torbu. = I see the bag.
• Ne vidim torbu. = I don’t see the bag.

So Serbian does not switch this object to another case here just because the sentence is negative. The form torbu remains correct.

Vidim is the 1st person singular present tense form of videti (to see).

So:

• ja vidim = I see
• ti vidiš = you see
• on/ona/ono vidi = he/she/it sees

In the sentence:

• ne vidim = I do not see

Serbian often omits the pronoun ja because the verb ending already shows who the subject is.

So Ne vidim already clearly means I don’t see.

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

The ending -im in vidim already tells you the subject is I.

So:

• Ja ne vidim torbu. = correct, but more explicit
• Ne vidim torbu. = also correct, and more natural in many contexts

If you add ja, it can give extra emphasis, such as contrast:

• Ja nigde ne vidim torbu, a on je vidi.
• I don’t see the bag anywhere, but he sees it.

Yes. Serbian word order is more flexible than English word order, because case endings help show each word’s role.

These are all possible, though they may differ slightly in emphasis:

• Nigde ne vidim torbu.
• Torbu nigde ne vidim.
• Ne vidim torbu nigde.

The original sentence puts emphasis early on nigde: nowhere.

That makes it sound natural if the main point is that you have looked around and the bag is visible nowhere.

In Serbian, ne is usually written separately from verbs:

• ne vidim = I do not see
• ne znam = I do not know
• ne mogu = I cannot

So ne vidim is the normal spelling.

There are a few important exceptions in Serbian, but for ordinary verbs like videti, the negative particle ne stays separate.

Because videti and gledati are not the same.

• videti / vidim = to see / I see
• gledati / gledam = to look at, watch

So:

• Ne vidim torbu. = I don’t see the bag.
• Ne gledam torbu. = I’m not looking at the bag.

In your sentence, the idea is that the bag is not visible to me anywhere, so vidim is the correct verb.

A simple pronunciation guide is:

NEEG-deh neh VEE-deem TOR-boo

More roughly by word:

• Nigde ≈ NEEG-deh
• ne ≈ neh
• vidim ≈ VEE-deem
• torbu ≈ TOR-boo

A few helpful notes:

• g is always a hard g as in go
• r is rolled or tapped
• vowels are usually clear and short, not reduced like in English

Yes, it is completely natural.

Nigde ne vidim torbu. is a normal way to say that the bag is not visible anywhere.

Depending on context, Serbian speakers might also say things like:

• Ne vidim torbu nigde.
• Torbu nigde ne vidim.

But your original sentence is grammatical, natural, and useful.