Kâğıdı imzalamadan önce dikkatlice okuyorum.

Because kâğıdı is the definite direct object of the sentence.

In Turkish, when a direct object is specific/definite, it usually takes the accusative ending. So:

• kâğıt = paper
• kâğıdı = the paper / the specific paper

Here, the speaker is talking about a particular paper, not just paper in general.

This happens because of a common sound change in Turkish.

The base word is kâğıt, but when a vowel-initial suffix is added, the final t often becomes d:

• kâğıt
• kâğıd-ı

So the form becomes kâğıdı, not kâğıtı.

This is very common in Turkish:

• kanat → kanadı
• ağıt → ağıdı
• kitap → kitabı

This is a very common Turkish pattern meaning before doing something.

It breaks down like this:

• imzala- = sign
• -madan / -meden = without doing / before doing in this pattern
• önce = before

So:

• imzalamadan önce = before signing

As a whole, verb + -madan/-meden önce is a set phrase learners should remember as:

• gelmeden önce = before coming
• gitmeden önce = before going
• yemeden önce = before eating

Even though -madan/-meden by itself often means without doing, with önce it is naturally understood as before doing.

Because Turkish often leaves out subject pronouns when the verb already shows who the subject is.

The ending in okuyorum tells you the subject is I:

• oku-yor-um
• read - present continuous - I

So ben is unnecessary unless the speaker wants emphasis:

• Ben kâğıdı imzalamadan önce dikkatlice okuyorum.

That would mean something like I read it carefully before signing, possibly contrasting with someone else.

Okuyorum is the present continuous form, and in Turkish it is often used for actions happening now or for what someone is currently doing in a situation.

• okuyorum = I am reading / I read
• okurum = I read, I usually read, I would read

In this sentence, okuyorum sounds natural if the speaker is describing their action in a real or immediate context: they read the paper carefully before signing it.

If you said okurum, it would sound more like a habit or general rule:

• Kâğıdı imzalamadan önce dikkatlice okurum.
  = I read the paper carefully before signing it / I always read papers carefully before signing.

So the difference is mainly about current/immediate action versus habitual/general action.

Dikkatlice is an adverb, and it means carefully.

It describes how the reading is done:

• dikkatlice okuyorum = I read carefully

Turkish often forms adverbs like this with -ce / -ca, though not every adverb is formed in exactly the same way.

A very common alternative is:

• dikkatli bir şekilde

So both can express carefully, but dikkatlice is shorter and very natural here.

Because Turkish usually puts adverbs before the verb they modify.

So:

• dikkatlice okuyorum = I read carefully

This is the normal word order in Turkish. Since Turkish is generally a verb-final language, a lot of information appears before the main verb.

The sentence structure is roughly:

• kâğıdı = object
• imzalamadan önce = time clause
• dikkatlice = manner adverb
• okuyorum = main verb

That is very natural Turkish word order.

Turkish usually follows a Subject–Object–Verb pattern, and the main verb often comes at the end.

In this sentence, the order is roughly:

• kâğıdı = the object
• imzalamadan önce = before signing
• dikkatlice = carefully
• okuyorum = I read / I am reading

So Turkish tends to build up the context first and then give the main verb last.

English usually says something more like:

• I read the paper carefully before signing it.

Turkish prefers:

• the paper + before signing + carefully + I read

This difference in word order is very important for English speakers to get used to.

Because Turkish often leaves out words that are already clear from context.

Here, kâğıdı is stated at the beginning, and it is easy to understand that the thing being signed is the same paper being read.

So the sentence naturally means:

• I read the paper carefully before signing it

Turkish does not need to repeat the object if it is obvious.

If you wanted to make it more explicit, you could say something like:

• Kâğıdı, onu imzalamadan önce dikkatlice okuyorum.

But that is less natural in many normal contexts because the original sentence is already clear.

Yes. A common alternative is imzalamadan evvel, since evvel also means before.

So you could say:

• Kâğıdı imzalamadan evvel dikkatlice okuyorum.

This means the same thing, but önce is more common in everyday modern Turkish.

Another possible style is using a noun-like form:

• İmzalamadan önce = before signing

This is already one of the most natural and standard ways to express that idea, so it is a very useful pattern to learn well.