Learn Hardcore Turkish: O kitap okurken ben de sessizce not alıyorum. - While she is reading a book, I also quietly take notes.

Could o ever mean that?
Yes, o can also be a demonstrative (that), as in o kitap = that book. But for that meaning here, you would normally change the verb to passive or add an object marker, e.g.:

O kitap okunurken = While that book is being read
O kitabı okurken = While (someone) is reading that book

Because the sentence is O kitap okurken, with no passive marker and no case on kitap, the natural reading is “While he/she is reading a book”.

What is the function of -ken in okurken?

The suffix -ken attached to a verb stem or tense marker means “while …ing” / “when …” and creates a kind of time clause.

oku- = to read
(oku) -ur / -yor → stems used with -ken
okurken = while (someone) is reading

Core idea: “during the time that the action is happening”.

Other examples:

Yürürken müzik dinliyorum. = I listen to music while walking.
Yemek yerken konuşmuyoruz. = We don’t talk while eating.

So O kitap okurken = While he/she is reading a book.

Why is it okurken and not okuyorken?

Both okurken and okuyorken are used in Turkish and are understood.

Historically and in more careful speech:
- okuyorken = while (he/she) is reading (literally built on okuyor “is reading”)
In everyday speech and writing, the -yor part is often simplified before -ken:
- okurken is more common and sounds more natural and fluent.

In practice, you’ll see and hear:

okurken (very common, natural)
okuyorken (more explicit, a bit heavier, still correct)

So your sentence uses the more colloquial and usual form okurken.

Why is there no bir before kitap? Shouldn’t it be bir kitap?

Bir means a / one, but in Turkish you don’t always have to use it where English uses a.

In O kitap okurken:

kitap without bir can mean “a book” in a general, non‑specific way.
If you say O bir kitap okurken, it often sounds like you’re emphasizing “a book (as opposed to something else)”, or focusing on the existence of a book.

So:

O kitap okurken… → While he/she is reading a book (neutral)
O bir kitap okurken… → While he/she is reading a (certain) book / an actual book (more marked, unusual in this sentence)

Leaving bir out is very normal and usually the most natural choice unless you need emphasis or exact counting.

What does ben de mean, and how is it different from bende?

ben de (two words) and bende (one word) are completely different.

ben de = I also / me too / I, for my part

ben = I
de = also / too (a separate particle, written separately)

In the sentence:

O kitap okurken ben de sessizce not alıyorum.
While he/she is reading a book, I’m also quietly taking notes.

Here ben de means I too / I also.

bende (one word) = on me, at me, with me (locative form of ben)

ben
- -de (locative suffix) → bende
Example: Anahtar bende. = The key is with me / on me.

So, in your sentence, it must be ben de (two words), not bende.

Why is the word order O kitap okurken ben de sessizce not alıyorum? Could I move parts around?

Turkish word order is flexible, but there are preferences for naturalness and emphasis.

The sentence is naturally divided like this:

O kitap okurken = While he/she is reading a book (time clause)
ben de sessizce not alıyorum = I am also quietly taking notes (main clause)

Putting the time clause at the beginning is very common:

O kitap okurken, ben de sessizce not alıyorum. (natural, neutral)

You could say:

Ben de sessizce not alıyorum, o kitap okurken.

This is grammatically fine but puts a bit more emphasis on what I am doing, with the “while he/she is reading” added after, almost like an afterthought.

Within the main clause:

ben de sessizce not alıyorum
You can usually move ben de and sessizce around somewhat:
Ben de not alıyorum sessizce. (still understandable)
Sessizce ben de not alıyorum. (emphasis on quietly)

But not alıyorum (the verb phrase) tends to stay at or near the end of the clause, because verbs are normally sentence-final in Turkish.

So, O kitap okurken ben de sessizce not alıyorum is a very natural and standard ordering.

What does sessizce mean exactly, and what is the role of -ce?

sessiz = silent / quiet (adjective)
sessizce = quietly (adverb)

The suffix -ce / -ça / -çe / -ca often turns adjectives or nouns into adverbs, similar to -ly in English.

yavaş → yavaşça = slow → slowly
dikkatli → dikkatlice (or more commonly dikkatle) = careful → carefully
Türk → Türkçe = Turkish (person) → Turkish (language) / in Turkish

So:

sessiz (quiet) + -ce → sessizce = quietly / in a quiet way

In your sentence, sessizce modifies not alıyorum:

sessizce not alıyorum = I am taking notes quietly.

Why does not almak mean to take notes? Isn’t not an English word?

Yes, not is a loanword from European languages (via French/English note). Modern Turkish uses many such loanwords.

not = note (as in written note, school grade, etc.)
almak = to take

Together, not almak literally means “to take note(s)”, just like English take notes.

So:

not alıyorum = I am taking notes
not aldım = I took notes
not almayı seviyorum = I like taking notes

This is the standard, natural verb for “taking notes” in Turkish.

Why is it not alıyorum (singular) and not notlar alıyorum (plural) if the English meaning is “I’m taking notes”?

In Turkish, the object does not always need a plural ending even when the meaning is plural or uncountable.

not almak is treated as a fixed expression meaning “to take notes”, and not here is almost like a mass noun:

not alıyorum naturally means “I’m taking notes”, not “I’m taking a single note”.

You can say notlar alıyorum, but that:

Sounds more marked, and
Emphasizes many separate notes or perhaps different types of notes.

Normally, for the general idea of taking notes during an activity, you use not alıyorum.

Why is the main verb alıyorum in the present continuous? Could it be another tense?

alıyorum is present continuous:

al- = take
-ıyor = present continuous marker
-um = 1st person singular

So alıyorum = I am taking (right now / around now).

It matches nicely with okurken (“while he/she is reading”), describing an ongoing simultaneous action.

Other possibilities:

O kitap okurken ben de sessizce not alıyordum.
While he/she was reading a book, I was quietly taking notes.
(Both in the past, continuous.)
O kitap okurken ben de sessizce not aldım.
While he/she was reading a book, I (at some point) took notes.
(Your note-taking seen more as a completed event.)

The present continuous -iyor matches English “am …ing” quite well in this context.

Do I have to say ben, or can I just say O kitap okurken, de sessizce not alıyorum?

You cannot drop ben and leave only de. The particle de needs something to attach its meaning “also / too” to.

ben de = I also
If you omit ben, de has no subject to relate to.

However, you can drop ben completely if you also drop de, because the verb ending -um already shows that the subject is I:

O kitap okurken sessizce not alıyorum.
While he/she is reading a book, I am quietly taking notes.

This is grammatical and would be understood as “I” even without ben.

So:

O kitap okurken ben de sessizce not alıyorum. → I’m also taking notes.
O kitap okurken sessizce not alıyorum. → I’m taking notes (no “also”).

But ✗ O kitap okurken de sessizce not alıyorum. is wrong in standard Turkish.

Is a comma needed: O kitap okurken, ben de sessizce not alıyorum?

In actual Turkish writing:

Many people do put a comma after such an initial time clause:
- O kitap okurken, ben de sessizce not alıyorum.
Others may omit it:
- O kitap okurken ben de sessizce not alıyorum.

Both are acceptable in everyday usage.

From a clarity standpoint, especially for learners, the comma can help you see the structure:

[O kitap okurken], [ben de sessizce not alıyorum].

So using a comma here is a good habit, but not absolutely required in informal writing.