Ben kitabı masanın üstüne koyuyorum.

Yes. In Turkish, the verb ending already shows the subject:

• koyuyorum = I am putting

So ben is often optional. It may be included for:

• emphasis: I am putting it
• contrast: I am putting it, not someone else
• clarity in context

So this sentence could also simply be:

• Kitabı masanın üstüne koyuyorum.

Because it is the definite direct object.

In Turkish, a specific object often takes the accusative ending:

• kitap = a book / book
• kitabı = the book (as a specific object)

Here, the speaker is putting a particular book somewhere, so kitabı is used.

There is also a sound change:

• kitap
  • -ı → kitabı

The final p changes to b when a vowel-initial ending is added. This is a common Turkish consonant alternation.

Because Turkish expresses on top of the table with a structure that literally works like:

• the table’s top

So:

• masa = table
• masanın = of the table / the table’s

This is the genitive ending.

The full phrase is:

• masanın üstüne = onto the top of the table

This is very natural in Turkish. Instead of using a simple preposition like English on, Turkish often uses a relational noun such as üst (top, upper side).

Üstüne means something like onto its top or on top of it.

It can be broken down like this:

• üst = top / upper side
• -ü = its
• -ne = to / onto

So:

• üstüne = onto its top

In masanın üstüne, the its refers back to table, so the whole phrase means:

• onto the table
• more literally: onto the top of the table

Because the sentence expresses movement toward a place, not location at a place.

• üstüne = onto / to the top of
• üstünde = on / on top of

Compare:

• Kitabı masanın üstüne koyuyorum. = I am putting the book onto the table.
• Kitap masanın üstünde. = The book is on the table.

So -e / -a-type meaning is used for direction, while -de / -da is used for location.

Because the most neutral Turkish word order is usually Subject – Object – Verb.

So in this sentence:

• Ben = subject
• kitabı = object
• masanın üstüne = place/direction phrase
• koyuyorum = verb

Turkish commonly puts the verb last.

English speakers often notice this first because English usually puts the verb earlier:

• I am putting the book onto the table.

Turkish word order can change for emphasis, but verb-final order is the standard pattern.

Koyuyorum means I am putting or I am placing.

It comes from:

• koymak = to put / to place

And in this sentence:

• koy- = verb stem
• -uyor = present continuous/progressive
• -um = I

So:

• koyuyorum = I am putting

This is the Turkish present continuous suffix, often written in dictionary-style explanations as -iyor / -ıyor / -uyor / -üyor.

Which form appears depends on vowel harmony.

Since the verb stem is koy-, the vowel before the suffix leads to:

• koy + uyor → koyuyor

Then add the first-person ending:

• koyuyorum

So the sentence is specifically about an action in progress:

• I am putting...

Turkish does not have English-style articles like the and a/an.

Whether something is definite or indefinite is usually understood from:

• context
• case endings
• word choice

In this sentence:

• kitabı clearly refers to a specific book because of the accusative ending
• masanın refers to the table in context

So Turkish can express the meaning without separate words like the.

Yes.

A very natural version is:

• Kitabı masanın üstüne koyuyorum.

This still means I am putting the book onto the table, because -um in koyuyorum already tells us the subject is I.

Turkish can also change word order for emphasis. For example:

• Masanın üstüne kitabı koyuyorum.
• Kitabı ben masanın üstüne koyuyorum.

These are still understandable, but they may shift focus or emphasis. The original sentence is a clear, standard form for learners.

Yes, there is a difference.

• koymak = to put / place something somewhere
• bırakmak = to leave / let go / put down, depending on context

In this sentence, the speaker is deliberately placing the book onto the table, so koymak is the most natural choice.

• kitabı masanın üstüne koymak = to put the book onto the table

If you used bırakmak, the feeling could be a bit different depending on context, sometimes more like leave or set down rather than simply place.