Doğruyu biliyorum.

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Breakdown of Doğruyu biliyorum.

• doğru: the truth

Questions & Answers about Doğruyu biliyorum.

What is doğruyu made of?

Doğruyu = doğru + -(y)u

• doğru can mean right, correct, or true
• here it is being used like a noun: the truth, the correct thing, or what is right
• -(y)u is the accusative ending

So doğru is not just an adjective here; it has been noun-like in this sentence.

Why does doğru take -yu here?

Because it is the definite direct object of the verb bilmek.

In Turkish, a direct object often takes the accusative ending when it refers to a specific/definite thing.

So:

• doğru = truth / what is correct
• doğruyu = the truth / the correct thing

That is why the sentence uses doğruyu, not just doğru.

Why is there a y in doğruyu?

The y is a buffer consonant.

Turkish often inserts y when:

• the word ends in a vowel
• and the suffix also begins with a vowel

Since doğru ends in u, and the accusative suffix here begins with a vowel, Turkish uses y to connect them smoothly:

• doğru + u would be awkward
• so it becomes doğruyu