selam , i still a beginner in turkish ; it ´s the first time i use the forum , but i m learning from the lessons of this site ; it´s so grate .

 for that i have a question about the plural ; i know that when we have numerical adjectives or indefinitive adjectives we don´t add(ler or lar ) : so i want to be shure when i use a number as 2 : exemple 

"ben iki kitap istyorum " i use kitap not kitaplar ! Is it right ? 

Yes. That´s correct.

Even without specifying a number, it can be different from English

Consider "I like apples."

I have seen both:

Elmaları severim.

Elma severim.

Ah ok çok teşekkur . 

I would think the first one means ´I like the apples´ whereas the second one means ´I like an apple´. 

http://www.turkishclass.com/turkish_lesson_256 

Here is where I got elma severim J:

http://tatoeba.org/eng/sentences/search?query=like+apples&from=und&to=tur

I thought for I like an apple: (Bir) elma seviyorum.

I think there is some grey area between what is general and what is specific.

Not sure...

Tatoeba is great and I use it a lot, but this is how it works: someone posts a sentence in Greek, someone translates it in Russian, someone then translates it in Turkish, someone then translates it in French, someone translates it in Dutch, and then someone translates it in English. When you see all the sentences together, they all have a slightly different meaning (some can be translated, other not). Then they start commenting on eachothers sentences, urging the translators to make a little change, then all the languages have to be changed and then it´s a big mess.To be really sure you should compare a few languages if you can. The first sentence (the source) should be leading.

Anyway, as far as I can understand it the ´ı´ in ´elmaları´ kindof means ´the´. You can check here:

http://www.turkishlanguage.co.uk/defarts.htm 

I quote from "Turkish Direct Object Suffix the":

The subject is already understood as substantive in Turkish, so it does not need a definite article. The subject definite Article the does not exist in Turkish, there is no "The man" as the subject definite article the is already understood.
However there is an object definite article the in Turkish which appears as the suffix -(y)i -(y)ı -(y)ü -(y)u or -ni -nı -nü -nu for already suffixed nouns.

Noun ending in a consonant: kilit the lock
Adam kilidi [kilid-i] kapattı The man locked THE LOCK
The -i suffix makes the bare noun kilit THE LOCK substantive as a direct object

-(y)i suffix works only when the noun is at object position. What if it is the subject?

I would say "bir" makes a noun indefinite otherwise it´s definite:

A man loves a woman = bir adam bir kadını sever

The man loves the woman = Adam kadını seviyor.

And even if it is at object position there are some cases -(y)i is not used.

The man is asking the woman some questions = Adam kadına sorular soruyor.

Oh no!? Because Tatoeba is my main source of learning!

I thought there was some flexibility here because with the apples - we are referring to a definite type of fruit but we aren´t refering to a definite group of apples.

Oh native speaker, please rescue us.

If someone asks, "what kind of food do you like?" which of these are acceptable answers?

1. Elma severim.

2. Elmayı severim.

3. Elmalar severim. (I think this one is wrong but I don´t know why?)

4. Elmaları severim.