Thread: какой-нибудь, какой-то, какой-либо и любой

This is exactly why I am telling Russian are killing me!!!!!

Посмотри, там кто-нибудь дерется? Look, are there anyone fighting?
Here we concentrate on the presence or absence of the fact of fighting.
The action itself is more interesting for us than who's actually performing it.

Посмотри, там кто-то дерется? Look, are there someone fighting? (not sure about the English variant)
Yes, there is someone fighting, and we wanna know, who exactly.

Посмотри, там кто-то дерется! - Declarative. Look, there's someone fighting. There is (someone certain) fighting.
It doesn't matter that we don't know who exactly. And we focus on the people who are fighting rather than on the action.
Посмотри, Там кто-нибудь дерется! - this is just wrong. Sounds like "Look, there's anybody fighting!"

A police officer is telling those 10 criminals, standing in front of him in a line.
I'm sure that someone of you, bast**ds, killed that guy. He uses Кто-ТО.
Я уверен, что кто-то из вас убил этого человека.

But if he's not sure if the killer is among them, he asks.
Убил ли кто-нибудь из вас этого человека?
(Sounds a bit weird for a Russian, but grammatically correct)

I don't claim that I read and understood everything but I have reached some conclusions. This post will be cornerstone of my future analysis
One sentence that puzzles me:
I have also to translate some documents of some other customers.
This will be translated as:
Мне следует перевести какие-то документы каких-то других клиентов.
Here the sentence is in future. Because I know very well documents which documents I will translated I use то instead of нибудь.
Correct?

P.S. On the sentences you wrote Medved a small correction
осмотри, там кто-нибудь дерется? Look, is there anyone fighting?
Here we concentrate on the presence or absence of the fact of fighting.
The action itself is more interesting for us than who's actually performing it.

Посмотри, там кто-то дерется? Look, is there someone fighting? (not sure about the English variant)
Yes, there is someone fighting, and we wanna know, who exactly.

Originally Posted by Antonio1986

I have also to translate some documents of some other customers.
This will be translated as:
Мне следует перевести какие-то документы каких-то других клиентов.

I'd say just "Мне надо перевести документы других клиентов."

Originally Posted by it-ogo

I'd say just "Мне надо перевести документы других клиентов."

For some reason I am confusing the words некоторый and the word какой-нибудь/то
For example:
1. This historical event is described in some books =
(a) это историческое событие описано в некоторых книгах
- I suppose that this implies that there are for example 10 books and the event is described in the 3 or 4 of them.
(b) это историческое событие описано в каких-нибудь книгах =
- The only thing I know here is that the event is descriped in some books but I don't have the slighest idea in how many.

Originally Posted by Antonio1986

For some reason I am confusing the words некоторый and the word какой-нибудь/то
For example:
1. This historical event is described in some books =
(a) это историческое событие описано в некоторых книгах
- I suppose that this implies that there are for example 10 books and the event is described in the 3 or 4 of them.
(b) это историческое событие описано в каких-нибудь книгах =
- The only thing I know here is that the event is descriped in some books but I don't have the slighest idea in how many.

I wrote a reply but it was lost due to site crash.

(a) Normally "некоторых" = "some of ..." that is a selection from some specified set is implied. "Существует много книг по этому периоду. В некоторых (из них) описано это событие."

(b) "это историческое событие описано в каких-нибудь книгах" = " I guess this event is described in some books (whatever thay are)." - But this usage is too specific. Much better "какие-нибудь" works in questions. "Описано ли это событие в каких-нибудь книгах? Да, оно описано в каких-то книгах." = "Do any books describe the event? Yes, some books do."