Ben evin kapısını onarıyorum.

I am repairing the house door.

Breakdown of Ben evin kapısını onarıyorum.

• ev: the house
• ben: I
• kapı: the door
• onarmak: to repair

Questions & Answers about Ben evin kapısını onarıyorum.

Why is ben optional in this sentence?

Turkish is a pro-drop language, meaning subject pronouns (ben, sen, o, etc.) can be omitted because the verb ending already indicates the person. In onarıyorum, the -um ending tells you it’s first-person singular (“I am repairing”). You include ben only if you want to emphasize “I” or contrast with someone else.

Why is it evin instead of ev?

To say “of the house,” the possessor noun takes the genitive case suffix -in (vowel-harmonized as -in/-ın/-un/-ün). Thus:
• ev (house) + -in ⇒ evin (“of the house”).

Why does kapı become kapısını? There seem to be two suffixes.

Indeed, kapısını carries:
1) A third-person singular possessive suffix -sı, yielding kapısı (“its door”).
2) An accusative suffix -ı for definite objects. Because kapısı ends in a vowel, a buffer n is inserted, giving -nı.

Breakdown:
kapı + -sı = kapısı (“its door”)
kapısı + -nı = kapısını (“its door,” as a specific direct object)

What role does the accusative suffix -ı play on kapısını?

In Turkish, definite or specific direct objects take the accusative suffix. Here you’re repairing a particular door (“the house’s door”), so you need -ı to mark it as a known, definite object. Without it, it would read as “I repair house door” in a general, non-specific sense.

How is the verb onarıyorum formed?

onarıyorum is the first-person singular present continuous of onarmak (“to repair”). The structure is:
1) Root: onar
2) Progressive suffix: -ıyor (from underlying -iyor, adjusted by vowel harmony)
3) Personal ending: -um (I)

So: onar + ıyor + um = onarıyorum (“I am repairing”).

Why is the progressive suffix sometimes written -iyor/-ıyor/-uyor/-üyor?

Turkish vowel harmony forces the vowel in -iyor to match the preceding vowel of the root:
• a/e ⇒ ı/i
• o/u ⇒ u/ı
• ö/ü ⇒ ü/ü

Since onar has a, the suffix becomes -ıyor, giving onarıyor.

Could I say Ben evin kapısını tamir ediyorum instead?

Yes. tamir etmek (“to repair/maintenance”) is very common in spoken Turkish. onarmak and tamir etmek are near-synonyms, though:
• tamir etmek is more colloquial.
• onarmak is slightly more formal or literary.

Is the Turkish word order always Subject–Object–Verb (SOV)?

The default is S-O-V, so Ben evin kapısını onarıyorum follows that pattern. You can rearrange elements for emphasis or style, but the verb usually stays last:
• Evin kapısını ben onarıyorum. (It’s I who am repairing the door.)
• Kapısını onarıyorum ben. (A more poetic or emphatic twist.)