Nekada sam živeo ovde.

Serbian often drops subject pronouns when they are not needed.

In sam živeo, the word sam already shows that the subject is I because it is the 1st person singular form of the auxiliary biti (to be) used in the past tense.

So:

• sam živeo = I lived
• si živeo = you lived
• je živeo = he lived

You can add ja for emphasis:

• Ja sam nekada živeo ovde. = I used to live here.

But in a neutral sentence, leaving out ja is completely normal.

This is the standard Serbian past tense, formed with:

• the present tense of biti (to be)
• plus the past active participle

So here:

• sam = am / 1st person singular auxiliary
• živeo = past participle of živeti (to live)

Together:

• sam živeo = I lived / I used to live

This is the normal way to make the past tense in Serbian.

The participle in Serbian agrees with the gender of the speaker in the singular.

So:

• živeo = masculine singular
• živela = feminine singular
• živelo = neuter singular

That means:

• A male speaker says Nekada sam živeo ovde.
• A female speaker says Nekada sam živela ovde.

This is one of the first things English speakers notice, because English past tense does not show the speaker’s gender.

In this sentence, nekada means something like:

• once
• at one time
• formerly
• in the past

Here it gives the idea of used to or formerly, not a single specific moment.

So Nekada sam živeo ovde suggests that living here was true in the past, but is not true now.

A useful comparison:

• nekada = once / formerly / in the past
• ponekad = sometimes

So don’t confuse:

• Nekada sam živeo ovde. = I used to live here.
• Ponekad živim ovde. would mean something like I sometimes live here, which is a very different idea.

Yes, very often they mean the same thing.

• nekada = full form
• nekad = shorter, very common form

Both can mean once, formerly, or in the past, depending on context.

So these are both natural:

• Nekada sam živeo ovde.
• Nekad sam živeo ovde.

The shorter form nekad is extremely common in everyday speech.

Because sam is a clitic.

In Serbian, clitics are short unstressed words that usually go in the second position of the clause, not wherever an English speaker might expect them.

In this sentence:

• Nekada is the first element
• sam comes right after it

So:

• Nekada sam živeo ovde.

This is very natural Serbian word order.

You can also move other elements for emphasis, but sam still tends to stay in second position within its clause:

• Ovde sam nekada živeo.
• Ja sam nekada živeo ovde.

English speakers often want to place sam directly after an implied subject, but Serbian clitic placement follows its own rules.

Yes. That is also correct.

Serbian word order is more flexible than English, so you can move parts of the sentence to change focus or emphasis.

Compare:

• Nekada sam živeo ovde.
  Neutral: I used to live here.

• Ovde sam nekada živeo.
  More emphasis on here.

• Ja sam nekada živeo ovde.
  More emphasis on I.

The meaning stays very similar, but the information structure changes a little.

Ovde means here, and it is an adverb of place.

That means it does not change for case, gender, or number. It simply tells you where.

So in this sentence:

• ovde = here

It is not a noun phrase, so you do not need to think about cases here.

Yes, depending on the regional standard.

Both mean here:

• ovde = common in Ekavian Serbian
• ovdje = common in Ijekavian varieties

Likewise, you may see:

• živeo in Ekavian-based Serbian
• živio in Ijekavian-based Serbian

So depending on region and standard, you might hear:

• Nekada sam živeo ovde.
• Nekada sam živio ovdje.

Both are natural in their respective varieties.

Because živeti is imperfective, and that fits the meaning.

Living somewhere is usually understood as an ongoing state or habitual situation, not a single completed event. In this sentence, the speaker is talking about a past situation that lasted for some time.

So the imperfective verb is exactly what Serbian wants here.

That is why Nekada sam živeo ovde sounds natural for:

• I used to live here
• I once lived here
• I lived here in the past

Usually it suggests a past state or period of life, not one single short event.

Because of nekada plus the imperfective verb živeti, the sentence normally means that at some earlier time, living here was part of the speaker’s life.

So it often feels close to English:

• I used to live here
• I once lived here

rather than something very momentary.

Yes.

You can say:

• Živeo sam ovde.

That simply means I lived here.

Adding nekada makes the idea of formerly / once / in the past more explicit:

• Živeo sam ovde. = I lived here.
• Nekada sam živeo ovde. = I used to live here / I once lived here.

So nekada adds a clearer contrast between then and now.

It is completely normal and natural in everyday Serbian.

Nothing in Nekada sam živeo ovde sounds unusually formal, literary, or old-fashioned. It is a standard, common sentence structure.

In casual speech, people might shorten it slightly:

• Nekad sam živeo ovde.

But the full version with nekada is also perfectly normal.