Learn Hardcore Turkish: Martılar göl kenarındaki kayalıklardan havalanıyor. - Seagulls are taking off from the rocks by the lakeside.

The -daki ending is a combination of the locative case suffix -de (meaning “at/in/on”) plus the relative-adjective suffix -ki (meaning “which is”). When you attach -de + ki to göl kenarı (“lakeside”), you get göl kenarındaki, literally “that which is at the lakeside.” It turns göl kenarı into a descriptor for whatever follows.

Why isn’t göl in the genitive case (i.e. gölün kenarı) before adding -daki?

Göl kenarı can function as a compound noun (“lakeside”) without any genitive or possessive markers. In compounds like this, Turkish often drops the genitive suffix -ün/-ın and the possessive -ı/-i. Once you have the compound göl kenarı, you treat it as one unit and then add -daki to kenar directly.

I see an n before -daki: why is it kenarındaki rather than kenar'daki or kenarıdaki?

In Turkish, when a noun ends in a vowel (here kenarı), and you attach suffixes that start with a vowel (here ki), you insert a buffer consonant n to avoid a vowel clash. So kenarı + ki becomes kenarı + n + daki → kenarındaki.

What case is -lardan in kayalıklardan, and what is its role here?

The suffix -lardan is the ablative case, formed from plural -lar + -dan (“from”). It indicates movement away from something. So kayalıklardan means “from the rocks.”

Why is kayalık in the plural form kayalıklar here?

Even if you picture one big rocky outcrop, Turkish often treats natural formations like “rocks” as a collection, so it uses the plural kayalıklar. The ablative then becomes kayalıklardan.

What is the verb havalanıyor, and how is it formed?

Havalanıyor is the present-continuous (or general present) form of the verb havalanmak, which means “to take off” or “to get airborne.”
Formation:

Root: havalan- (“become airborne”)
Continuous tense suffix: -ıyor
No personal ending (3rd person is zero-marked when the subject is clear)
Together: havalan + ıyor → havalanıyor (“(they) are taking off”).

Why doesn’t the verb have a plural ending like -lar (i.e. havalanıyorlar) to match martılar?

When the subject is explicitly plural (here martılar), Turkish allows you to drop the 3rd-person-plural suffix on the verb. So both martılar havalanıyor and martılar havalanıyorlar are correct, but the shorter form is more natural.

What’s the difference between havalanmak and uçmak?

uçmak simply means “to fly” (the action of flying).
havalanmak specifically means “to take off” or “to become airborne.”
In this sentence, the emphasis is on the moment the gulls lift off from the rocks, so havalanmak is the precise choice.

Could you use the simple present instead of -ıyor (continuous)? For example, martılar göl kenarındaki kayalıklardan havalanır?

Yes, havalanır is the simple present tense and is used for general truths or habits (“gulls take off from lakesides”). But if you’re describing an action happening right now or a vivid scene, the continuous -ıyor is preferred. Hence havalanıyor gives the sense “(right now) they are taking off.”