Learn Hardcore Turkish: Zeminin pürüzlü yüzeyi kaymayı engelliyor ancak adım atmayı yavaşlatıyor. - The floor’s rough surface prevents slipping but slows down walking.

The suffix -in is the genitive case marker indicating possession.
• zemin-in = “of the ground” or “ground’s.”
So zeminin pürüzlü yüzeyi literally means “the ground’s rough surface.”

Why does yüzey take the suffix -i (becoming yüzeyi)?

In a genitive-possessive construction, the possessed noun must agree with its possessor by taking a third-person possessive suffix:
• zemin-in (genitive) yüzey-i (possessive) = “the ground’s surface.”

Why is kaymayı used instead of kaymak?

• kaymak = infinitive “to slip.”
• kayma = gerund or verbal noun “slipping.”
• kaymayı = gerund plus the accusative suffix -ı, because it’s a definite object of engellemek (“to prevent”).
Thus kaymayı engelliyor means “(it) is preventing slipping.”

What role does the letter y play in kaymayı?

It’s a buffer consonant. Since kayma ends in a vowel and we want to add the vowel-initial suffix -ı, Turkish inserts y to preserve phonological rules:
kayma + y + ı → kaymayı

Why does adım atmak become adım atmayı in this sentence?

adım atmak = “to take a step.”
Form the gerund: adım atma (“stepping”).
Add accusative -yı (definite object): adım atma+yı → adım atmayı.
It’s the specific action being slowed down by yavaşlatmak.

Why are the verbs engelliyor and yavaşlatıyor in the present-progressive (-iyor) form?

The -iyor suffix can express:
• Ongoing actions (“is preventing,” “is slowing down”).
• General truths or characteristics (similar to English simple present).
Here it states a general property of the rough surface:
“It prevents slipping but slows down stepping.”

What does ancak mean, and can I use another conjunction?

ancak = “however,” “but.”
You can also use:
• ama (colloquial)
• fakat (formal)
Example with ama:
Zeminin pürüzlü yüzeyi kaymayı engelliyor ama adım atmayı yavaşlatıyor.

Could I say zeminde pürüzlü yüzey instead of zeminin pürüzlü yüzeyi, and what’s the difference?

Yes, but the meaning changes:
• zeminin pürüzlü yüzeyi (genitive-possessive) = “the ground’s rough surface.”
• zeminde pürüzlü yüzey (locative) = “a rough surface on the ground.”
Genitive shows ownership; locative shows location.

Why do engellemek and yavaşlatmak have the suffixes -le- and -lat-?

They’re causative formations:
• engel (noun “obstacle”) + -le- (make/do) + -mek = engellemek (“to cause an obstacle,” i.e. “to prevent”).
• yavaş (adj. “slow”) + -lat- (make) + -mak = yavaşlatmak (“to make slow,” i.e. “to slow down”).