Она принесла кое-какие документы.

Кое-какие means something like some, certain, or a few particular. It suggests that the speaker has some specific documents in mind, but either does not want to name them, does not think the exact details matter, or assumes the listener does not need the full list.

So кое-какие документы is not just a random some documents. It often has a nuance like:

• some particular documents
• certain documents
• a few documents

It can sometimes sound slightly vague but not completely indefinite.

This is a very common question, because both can be translated as some.

A useful rough distinction is:

• кое-какие = some particular ones, often known to the speaker
• какие-то = some kind of / some random / some unspecified, often vaguer

So:

• Она принесла кое-какие документы = she brought certain documents / some particular documents
• Она принесла какие-то документы = she brought some documents or other, possibly with more uncertainty or vagueness

In real speech, the difference is not always huge, but кое-какие often suggests a bit more intention or specificity.

Because кое- is a particle/prefix-like element that is written with a hyphen when attached to pronouns and related words.

So you get forms like:

• кое-кто
• кое-что
• кое-какой
• кое-где

In this sentence, кое-какие is the plural form of кое-какой.

Because the subject is она, and in the past tense Russian verbs agree with the subject in gender and number.

Past tense forms:

• он принёс = he brought
• она принесла = she brought
• оно принесло = it brought
• они принесли = they brought

So принесла is the feminine singular past form, matching она.

The infinitive is принести, meaning to bring.

This verb is a bit irregular in the past tense:

• принести → принёс, принесла, принесло, принесли

So the form does not look exactly like the infinitive stem, which is something learners often notice.

This is about aspect.

• принести is perfective
• приносить is imperfective

Она принесла кое-какие документы uses the perfective verb because it describes a completed action: she brought the documents, and the result is that they are now there.

If you said она приносила кое-какие документы, it would usually mean something more like:

• she used to bring some documents
• she was bringing some documents
• she brought some documents on one occasion, with focus on the process or fact rather than the completed result

In this sentence, the natural choice is принесла because the action is presented as finished.

Документы is in the accusative plural, because it is the direct object of принесла.

The tricky part is that for inanimate plural nouns, the accusative looks the same as the nominative.

So:

• nominative plural: документы
• accusative plural: документы

That is why the form does not change here.

Because it has to agree with документы in number, case, and roughly like an adjective.

Here, документы is:

• plural
• accusative
• inanimate

So кое-какие also appears in the matching plural form: кое-какие.

You can think of it as behaving similarly to an adjective-like word modifying the noun.

Russian has no articles. There is no direct equivalent of English a/an or the in ordinary grammar.

So Она принесла кое-какие документы can be interpreted from context as something like:

• she brought some documents
• she brought certain documents
• she brought the documents we were talking about

Russian usually leaves this to context, word choice, and emphasis.

In this sentence, кое-какие already gives an indefinite-but-specific sense, so no article is needed.

Yes. Russian word order is more flexible than English, and changing it often changes the emphasis, not the basic meaning.

Neutral order:

• Она принесла кое-какие документы.

Other possible orders:

• Кое-какие документы она принесла.
• Документы она принесла кое-какие.
  (more marked, more conversational, and not the most neutral)

The original sentence is natural and neutral. It simply states the fact that she brought certain documents.

In this sentence, yes, because документы is plural and кое-какие agrees with it.

But the base form can appear in other genders and numbers depending on the noun:

• кое-какой документ = some particular document
• кое-какая книга = some particular book
• кое-какое письмо = some particular letter
• кое-какие документы = some particular documents

So the form changes to match the noun, just like an adjective would.