Learn Hardcore Turkish: Pazartesi günü kütüphanede ders çalışacağım.

These two mean the same thing in everyday speech. Pazartesi günü can feel slightly more explicit or “complete,” but it’s not more future or more formal in any strong way; it’s just a very common pattern with days:
Pazartesi günü, Salı günü, Çarşamba günü, etc.

What does günü literally mean in Pazartesi günü?

Literally:

gün = “day”
günü = “the day / its day” (gün + third-person possessive + accusative, historically)

So Pazartesi günü is like saying “Monday’s day” or “the day which is Monday.”

You don’t need to think about all the morphology every time; just remember that:

Pazartesi günü is a set pattern meaning “on Monday”.
The same structure works with other time words:
- doğum günüm = my birthday (my birth day)
- tatil günü = holiday (day of vacation)

Why is there no word for “on” before Monday, like in English “on Monday”?

Turkish usually doesn’t use separate prepositions like on, in, at for time. Instead, it uses:

Bare time words:
- Pazartesi kütüphanede ders çalışacağım.
  → “(On) Monday I will study at the library.”
Time words with günü:
- Pazartesi günü kütüphanede ders çalışacağım.
  → “On Monday I will study at the library.”

So Pazartesi (günü) itself functions as “on Monday.” You simply put the time expression (Pazartesi, yarın, bu akşam, etc.) before the rest of the sentence without a preposition.

Why is there no word for “at” before “the library”? What does the -de in kütüphanede do?

Turkish uses suffixes instead of separate prepositions like in, at, on.

kütüphane = library
kütüphane + -de = kütüphanede = “in the library / at the library”

The suffix -de / -da is called the locative case. It usually corresponds to:

in: kütüphanede = in the library
at: evde = at home
on (sometimes): masada = on the table

So the English “at the library” is expressed as one word in Turkish, kütüphanede.

Why is it kütüphane + -de and not -da? When do we use -de vs -da?

The choice between -de and -da follows vowel harmony and consonant harmony rules:

After a word ending in a voiced consonant (like n, l, r, b, c, d, g, ğ, v, z), you use -de or -te.
After a word ending in a voiceless consonant (like p, ç, t, k, f, s, ş, h), you use -ta or -te.

For kütüphane:

It ends with a vowel -e.
The vowel in the suffix is e (front vowel harmony).
The consonant in the suffix is d (voiced, default).

So: kütüphane + -de → kütüphanede

Some more examples:

ev + -de → evde (at home)
okul + -da → okulda (at school)
park + -ta → parkta (in the park)
iş + -te → işte (at work)

What exactly does ders çalışmak mean? Why not just çalışmak?

çalışmak alone means “to work,” and depending on context, it can mean:
- to work (do a job)
- to study (put effort into learning), but this is less explicit
ders = “lesson, class, course”
ders çalışmak literally “to work lesson,” but idiomatically it means:
- “to study (for school/lessons)”

So:

çalışacağım could be “I will work” or “I will study,” depending on context.
ders çalışacağım is clearly “I will study (my lessons).”

Using ders çalışmak is the standard way to say to study (for school/exams) in Turkish.

How is the verb çalışacağım formed? What are its parts?

çalışacağım is made of:

çalış- – the verb stem: “to work / to study”
-acak- – future tense suffix (“will …”)
-ım – 1st person singular ending (“I”)

In a simple breakdown:

çalış- + -acak + -ım → çalışacağım

Spelling changes happen due to vowel harmony and pronunciation, but conceptually it’s:

stem + future + personal ending = “I will [verb].”

Other persons:

çalışacağım – I will work/study
çalışacaksın – you (sg) will work/study
çalışacak – he/she/it will work/study
çalışacağız – we will work/study
çalışacaksınız – you (pl/formal) will work/study
çalışacaklar – they will work/study

What’s the difference between çalışacağım and çalışıyorum?

çalışacağım = future tense → “I will work / I will study”
çalışıyorum = present continuous → “I am working / I am studying (right now)”

In terms of meaning:

Pazartesi günü kütüphanede ders çalışacağım.
→ I will study at the library on Monday. (future plan)
Pazartesi günü kütüphanede ders çalışıyorum.
→ I study at the library on Monday.
(could mean a scheduled plan, like “I’m studying at the library on Monday” / “My plan is that I’ll be studying then.”)

For a clear future, especially when first announcing a plan, -acak/-ecek is the default choice: çalışacağım.

Why don’t we see ben (“I”) in the sentence? How do we know it means “I will study”?

Turkish doesn’t have to use subject pronouns when the verb ending already shows the person.

çalışacağım ends in -ım (in this form it appears as -m sound plus the preceding vowel), which marks “I”.
So the verb itself carries the subject information.

You can say:

Ben Pazartesi günü kütüphanede ders çalışacağım.
→ perfectly correct, adds emphasis on “I”

But normally, if there’s no contrast or emphasis, Turkish drops the subject pronoun:

Pazartesi günü kütüphanede ders çalışacağım.
→ “I will study at the library on Monday.” (subject understood from verb)

Is the word order fixed? Can I move parts around in this sentence?

Turkish word order is relatively flexible, but the default neutral order is:

[Time] – [Place] – [Object] – [Verb]

So the sentence follows a natural pattern:

Pazartesi günü (time)
kütüphanede (place)
ders (object)
çalışacağım (verb)

Other possible orders:

Kütüphanede Pazartesi günü ders çalışacağım.
Ders çalışacağım Pazartesi günü kütüphanede.

These are grammatically possible, but may sound marked or emphasize different parts. For learners, it’s best to stick to the neutral pattern:

Time – Place – [Object] – Verb

How would I say “On Mondays I study at the library” (habitually) instead of just one Monday?

To express a habit (“on Mondays in general”), Turkish usually pluralizes the day:

Pazartesi günleri kütüphanede ders çalışıyorum.

Breakdown:

Pazartesi günleri = “on Mondays” (every Monday / most Mondays)
ders çalışıyorum = “I am studying / I study” (present continuous used for habitual actions too)

Compare:

Pazartesi günü ders çalışacağım.
→ I will study on Monday (this coming/specific Monday).
Pazartesi günleri ders çalışıyorum.
→ I (generally) study on Mondays.

Why is Pazartesi capitalized? Is that always the case?

Yes. In Turkish, days of the week and months are capitalized, just like in English.

So you write:

Pazartesi, Salı, Çarşamba, Perşembe, Cuma, Cumartesi, Pazar
Ocak, Şubat, Mart, Nisan, ...

Therefore:

Pazartesi günü kütüphanede ders çalışacağım.
→ Pazartesi is capitalized because it’s the name of a specific day.