Learn Hardcore Turkish: Silgiyi alıp defterdeki hatayı sildim. - I took the eraser and erased the mistake in the notebook.

-Ip is a converb that links two actions with the same subject and usually means “and (then)”.
Silgiyi alıp hatayı sildim ≈ “I took the eraser and erased the mistake.”
You can also say two finite clauses: Silgiyi aldım ve hatayı sildim. This is slightly less “tight” than -ıp.
Don’t combine them as alıp ve sildim; that’s unidiomatic.

Why is silgiyi in the accusative? Could it be silgi?

Accusative (-ı/-i/-u/-ü) marks a specific/definite direct object.
Silgiyi alıp… = “I took the (specific) eraser.”
Silgi alıp… = “I took an eraser.” (non-specific)
The extra -y- in silgiyi is a buffer consonant because the noun ends in a vowel.

Why is hatayı in the accusative? Could I say defterdeki hata sildim?

Hatayı is the specific object of sildim, so it takes accusative.
Defterdeki hatayı sildim = “I erased the mistake (that’s) in the notebook.”
If you mean an indefinite mistake, say Defterde bir hata sildim (“I erased a mistake in the notebook”).
Defterdeki hata sildim is unnatural; the modifier defterdeki tends to make the noun specific in this context.

What exactly is defterdeki? How does -ki work?

defter-de-ki = notebook-LOC-REL “the one that is in the notebook.”
-de is the locative “in/on/at.” -ki turns that phrase into an adjectival modifier.
So defterdeki hata = “the mistake (that is) in the notebook.”
In standard Turkish, -ki generally does not follow vowel harmony and stays -ki (a few set expressions like bugünkü exist).

Why not say defterin hatası?

Defterin hatası means “the notebook’s own fault/defect,” as if the notebook itself is defective.
Defterdeki hata points to a mistake located in the notebook (e.g., something written in it). That’s the intended meaning here.

Is the word order fixed? Can I move parts around?

Turkish allows flexible order for emphasis/focus.
Variants like Defterdeki hatayı, silgiyi alıp sildim or Silgiyi alıp, defterdeki hatayı sildim are acceptable.
Moving an element to the front often highlights it.

Do I need a comma after alıp?

It’s optional. Many writers add a comma after a converb clause for readability: Silgiyi alıp, defterdeki hatayı sildim.
In short sentences, leaving it out is common.

Can I just say Silgiyi aldım, defterdeki hatayı sildim? Any nuance difference?

Yes. Two finite clauses are fine.
-Ip tends to imply a tighter, immediate sequence or a step toward the main action. Two past-tense clauses feel more like two separate events.

Could I say Silgiyi alarak defterdeki hatayı sildim?

-erek/-arak often means “by/while doing,” indicating manner or simultaneity.
For a clear “first X, then Y” sequence, -ıp is more natural.
Other sequential options: Silgiyi alınca… (“when I took it…”) or Silgiyi aldıktan sonra… (“after taking it…”).

How would I say it if I only want to express the instrument, not the act of picking it up?

Use the instrumental -le/-la: Silgiyle defterdeki hatayı sildim = “I erased the mistake with the eraser.”

What is the -y- in silgiyi and hatayı?

It’s a buffer consonant inserted when a vowel-final word takes a vowel-initial suffix: silgi + i → silgiyi, hata + ı → hatayı.

How does vowel harmony pick -ı/-i/-u/-ü in the accusative?

The accusative is underlying -I; it harmonizes with the last vowel of the noun:
- After a/ı → -ı (e.g., hata → hatayı)
- After e/i → -i (e.g., silgi → silgiyi)
- After o/u → -u
- After ö/ü → -ü

Can you break down the whole sentence morphologically?

Silgi-yi al-ıp defter-de-ki hata-yı sil-di-m
- silgi-yi = eraser-ACC
- al-ıp = take-CONV (-ıp converb “and then”)
- defter-de-ki = notebook-LOC-REL (“in the notebook” → adjectival)
- hata-yı = mistake-ACC
- sil-di-m = erase-PAST-1SG

What about the past tense in sildim?

sil-di-m = stem sil-
- past -DI
  - 1st sg -m.
-DI appears as -dı/-di/-du/-dü (and as -tı/-ti/-tu/-tü after voiceless consonants, e.g., bak-tı-m).

Does -ıp require the same subject for both actions?

Yes, the converb assumes the same subject for both verbs.
If the subjects differ, use two finite clauses or ve: Silgiyi ben aldım ve sen hatayı sildin.
Alternatively, use other subordination (e.g., Sen silgiyi alınca ben sildim).

Could defterdeki modify silgiyi instead? Is there any ambiguity?

By default, defterdeki modifies the noun right after it.
In the given sentence, it attaches to hatayı. To modify the eraser, say: Defterdeki silgiyi alıp hatayı sildim = “I took the eraser in the notebook and erased the mistake.”

How do I say it with a plural object?

Definite plural object: defterdeki hataları sildim = “I erased the mistakes in the notebook.” (hata-lar-ı = mistakes-ACC)
Indefinite quantity is often expressed with words like birkaç or bazı: Defterde birkaç hata sildim = “I erased a few mistakes in the notebook.”