Başucu kitabım komodinin yanında duruyor; gece lambası açık kalınca okuyabiliyorum.

Başucu kitabım means my bedside book or the book I keep by my bed.

A few useful points:

• başucu literally means bedside or the head side of a bed
• kitap = book
• kitabım = my book

As a whole, başucu kitabı is a common expression. It can mean:

• a book kept near the bed for reading
• sometimes, a favorite/reference book that someone keeps close at hand

So başucu kitabım is not just any book; it suggests my bedside book as a kind of set idea.

Because of a common sound change in Turkish.

The noun is kitap. When a vowel-initial suffix is added, the final p often changes to b:

• kitap = book
• kitabım = my book

This happens in many Turkish words with final p, t, k, ç when suffixes are attached.

Other examples:

• ağaç → ağacı
• renk → rengi
• kanat → kanadı

So kitabım is the normal correct form.

Because it is in the genitive form: of the bedside table.

• komodin = bedside table / nightstand
• komodinin = of the bedside table

This is needed because of yanında:

• yanı = its side
• yanında = at its side / next to it

So komodinin yanında literally works like:

• at the side of the bedside table

This is a very common Turkish pattern:

• evin önünde = in front of the house
• masanın üstünde = on the table
• kapının yanında = next to the door

Because this sentence describes location, not movement.

• yanında = beside / next to / at the side of
• yanına = to the side of / to beside, showing motion toward something

Here the book is already there:

• Başucu kitabım komodinin yanında duruyor. = My bedside book is sitting next to the nightstand.

If there were movement, you would use yanına:

• Kitabı komodinin yanına koydum. = I put the book next to the nightstand.

So:

• -da / -de = in/at/on
• -a / -e = to/toward

Not necessarily. In Turkish, durmak often means more generally:

• to stand
• to stay
• to be positioned
• to sit/be located somewhere

So duruyor here is very natural for an object and means something like:

• is there
• is sitting there
• is positioned there

For objects, Turkish often uses durmak where English might prefer be, sit, or lie.

So komodinin yanında duruyor means:

• it is next to the nightstand
• it is sitting next to the nightstand

It comes from:

• dur- = stand / stay
• -uyor = present continuous
• implied subject = it

So:

• duruyor = it is standing / staying / sitting there

The -iyor / -ıyor / -uyor / -üyor suffix is the usual present continuous suffix in Turkish.

Examples:

• okuyor = is reading
• gidiyor = is going
• duruyor = is standing / is staying

Because this is a Turkish noun compound.

• gece = night
• lamba = lamp
• gece lambası = night lamp / bedside lamp

In many Turkish noun compounds, the second noun takes a compound marker, often -(s)ı / -(s)i / -(s)u / -(s)ü.

So:

• okul kapısı = school door
• yatak odası = bedroom
• gece lambası = night lamp

That -sı does not mean his/her/its here. It is just part of the compound structure.

Yes, açık often means open, but with lights and electrical devices it commonly means on.

So:

• lamba açık = the lamp is on
• lamba kapalı = the lamp is off

This is very natural Turkish.

English speakers often expect a verb like turn on, but Turkish frequently uses the adjective açık for the resulting state.

So gece lambası açık means:

• the night lamp is on

Literally, it is something like:

• when it stays on
• when it remains on

It has two parts:

• açık = open / on
• kal- = remain / stay
• -ınca = when / once / whenever

So:

• açık kalınca = when it stays on or when it remains on

In this sentence, the natural English meaning is closer to:

• when the night lamp is left on
• if the night lamp stays on
• when the night lamp is on, I can read

-ınca / -ince / -unca / -ünce often means:

• when
• once
• whenever
• sometimes since/as depending on context

Here it connects the first action/state to the second:

• gece lambası açık kalınca okuyabiliyorum = when the night lamp stays on, I can read

It often gives a sense of:

• a condition being met
• a situation happening first
• a cause or enabling circumstance

More examples:

• Eve gelince beni ara. = Call me when you get home.
• Hava güzel olunca yürüyüşe çıkıyoruz. = When the weather is nice, we go for a walk.

So in your sentence, -ınca is introducing the situation that makes reading possible.

It is made from several pieces:

• oku- = read
• -y- = buffer consonant
• -abil- = be able to / can
• -iyor = present continuous
• -um = I

So:

• oku-y-abil-iyor-um
• okuyabiliyorum
• I can read / I am able to read

This is a very useful Turkish pattern:

• gidebiliyorum = I can go
• görebiliyorum = I can see
• anlayabiliyorum = I can understand

Because they do different jobs.

• -abil- adds the meaning of ability / possibility: can
• -iyor puts it in the present continuous / current present form

So okuyabiliyorum means:

• I can read
• more literally, I am able to read

This is very natural when talking about a present situation or current ability.

Compare:

• okurum = I read / I will read / I do read
• okuyorum = I am reading
• okuyabilirim = I may be able to read / I can read
• okuyabiliyorum = I am able to read, I can read

In this sentence, okuyabiliyorum fits well because the lamp being on creates the present ability to read.

Because Turkish has no articles like English a/an and the.

So nouns often appear without any separate article word:

• komodin can mean a nightstand or the nightstand
• gece lambası can mean a night lamp or the night lamp

The exact meaning depends on context.

That is why:

• Başucu kitabım komodinin yanında duruyor does not need a separate word for the before komodin.

Because Turkish normally places the finite verb at or near the end of the clause.

So the pattern is often:

• topic / subject
• other information
• verb

In your sentence:

• Başucu kitabım = subject/topic
• komodinin yanında = location
• duruyor = verb

and

• gece lambası açık kalınca = when the night lamp stays on
• okuyabiliyorum = I can read

This end-position verb pattern is one of the most basic features of Turkish word order.

The semicolon links two closely related clauses.

The first clause:

• Başucu kitabım komodinin yanında duruyor

The second clause:

• gece lambası açık kalınca okuyabiliyorum

The second clause explains a related circumstance: the book is there, and because the lamp stays on, reading is possible.

In Turkish, punctuation here is fairly flexible. A comma might also appear in some writing, but the semicolon gives a stronger separation while still showing the ideas are connected.