Sahil sessiz olunca akşam yürüyüşü daha keyifli oluyor.

Olunca comes from olmak (to be / to become / to happen) and means something like when it is, when it becomes, or sometimes once it is.

So Sahil sessiz olunca means:

• when the beach/coast is quiet
• or more naturally, when it’s quiet at the beach

This -ınca / -ince / -unca / -ünce form is very common for when/once clauses.

Examples:

• Eve gelince = when I come home
• Hava güzel olunca = when the weather is nice

In Turkish, adjectives can often act as the predicate by themselves in simple present statements.

So:

• Sahil sessiz. = The beach is quiet.

There is no separate word for is in that kind of sentence.

But when Turkish needs a structure like when it is quiet, it often uses olmak:

• sessiz olunca = when it is quiet

So sessiz is the adjective (quiet), and olunca supplies the when it is / when it becomes part.

Good question. The sentence contains two forms of olmak, but they do different jobs:

• sessiz olunca = when it is/becomes quiet
• keyifli oluyor = becomes/is getting more enjoyable

The first one creates the when-clause. The second one is the main verb of the sentence.

So the full structure is:

• [When the beach is quiet] [the evening walk becomes more enjoyable].

Oluyor is from olmak and here it means becomes or ends up being.

So:

• daha keyifli oluyor = becomes more enjoyable / is more enjoyable

If you only said:

• Akşam yürüyüşü daha keyifli.

that would mean The evening walk is more enjoyable, but it sounds a bit more like a plain statement.

Oluyor often gives a sense of:

• a resulting situation
• a general tendency
• something that turns out that way

So in this sentence, oluyor fits the idea that the walk becomes nicer under that condition.

This is a very common Turkish noun-compound pattern.

Akşam yürüyüşü means evening walk.

It is built like this:

• akşam = evening
• yürüyüş = walk
• yürüyüşü = walk + compound suffix

This is called an indefinite noun compound. In this pattern, the first noun modifies the second, and the second noun usually gets a third-person possessive-type suffix:

• kahve fincanı = coffee cup
• yaz tatili = summer vacation
• akşam yürüyüşü = evening walk

So the -ü is not random; it is part of a normal noun-compound structure.

Daha means more.

So:

• keyifli = enjoyable / pleasant
• daha keyifli = more enjoyable / more pleasant

It is the normal word used to form comparatives in Turkish.

Examples:

• daha güzel = more beautiful
• daha zor = more difficult
• daha sessiz = quieter

In your sentence, it means the evening walk is more enjoyable under that condition.

Keyifli means enjoyable, pleasant, or nice in a satisfying way.

It comes from keyif, which is a feeling of pleasure, enjoyment, or comfort.

So:

• keyifli bir gün = a pleasant day
• keyifli vakit geçirmek = to have a good/enjoyable time

In this sentence, daha keyifli oluyor means the walk feels more pleasant or more enjoyable.

Yes, in Sahil sessiz olunca, sahil is the thing being described as quiet, so it works as the subject of that clause.

Sahil can mean:

• coast
• shore
• seaside
• sometimes beach, depending on context

In everyday translation here, beach is often the most natural choice, but coast or seafront could also fit depending on the situation.

So the sentence could suggest:

• the beach itself is quiet
• the seafront area is quiet
• the coast/seaside is quiet

Turkish often leaves out pronouns when they are understood from context.

In English, we often say:

• when it is quiet
• it becomes more enjoyable

Turkish does not need an equivalent it in the same way.

So instead of saying something like it is quiet, Turkish can simply say:

• sessiz = quiet
• sessiz olunca = when it is quiet

And instead of it becomes more enjoyable, the sentence names the thing directly:

• akşam yürüyüşü daha keyifli oluyor

This is very normal in Turkish.

Turkish usually puts the main verb at the end, and time/condition phrases often come before the main clause.

So the sentence is structured like this:

• Sahil sessiz olunca = when the beach is quiet
• akşam yürüyüşü daha keyifli oluyor = the evening walk becomes more enjoyable

That gives:

When the beach is quiet, the evening walk becomes more enjoyable.

This order is very natural in Turkish.

Turkish word order is somewhat flexible, but this version sounds smooth and standard.

Yes, you could.

• sessiz olunca
• sessiz olduğunda

Both can mean when it is quiet.

But there is a slight difference in feel:

• olunca often sounds a bit more natural and compact in everyday speech
• olduğunda can sound a bit more explicit or formal

So:

• Sahil sessiz olunca akşam yürüyüşü daha keyifli oluyor.
• Sahil sessiz olduğunda akşam yürüyüşü daha keyifli oluyor.

Both are correct.

Not necessarily. Even though -yor is often introduced as the present continuous, in Turkish it can also describe:

• general truths
• repeated situations
• habits
• typical results

So here oluyor does not have to mean is becoming right now at this exact moment.

It can mean something like:

• tends to be
• usually becomes
• is generally

That is why the sentence works well as a general observation: When the beach is quiet, an evening walk is more enjoyable.