Şimşek çakınca ağaçlara yaklaşmamalısın.

Çakınca comes from the verb çakmak.

In this sentence, çakınca means when lightning flashes/when lightning strikes.

It is made from:

• çak- = the verb stem
• -ınca / -ince / -unca / -ünce = a suffix meaning when or once

So:

• şimşek çakınca = when lightning flashes

This structure is very common in Turkish:

• eve gelince = when he/she comes home
• seni görünce = when I see you

The exact form of the suffix changes because of vowel harmony.

Because Turkish uses a specific verb with şimşek: şimşek çakmak.

This is a set expression meaning lightning flashes.

So Turkish says:

• şimşek çakıyor = lightning is flashing
• şimşek çakınca = when lightning flashes

Even if it sounds unusual from an English point of view, it is the natural Turkish phrasing.

This is a very common question.

• şimşek usually refers to the flash of lightning
• yıldırım often refers more to the lightning bolt/strike

In everyday speech, people may sometimes use them loosely, but in this sentence şimşek çakmak is a normal expression.

So Şimşek çakınca... sounds natural.

Ağaçlara means to trees or to the trees.

It breaks down like this:

• ağaç = tree
• ağaçlar = trees
• ağaçlara = to the trees / toward the trees

The plural is used because the meaning is general: not just one tree, but trees in general.

English often says don’t go near trees in the plural too, so this matches well.

Because yaklaşmak is a verb that normally takes the dative case in Turkish.

So you approach toward something:

• eve yaklaşmak = to approach the house
• okula yaklaşmak = to approach the school
• ağaçlara yaklaşmak = to approach the trees

That is why you do not say ağaçları yaklaşmak here.

Yaklaşmamalısın means you should not approach or you shouldn’t go near.

It is built from several parts:

• yaklaş- = approach / get close
• -ma- = negation
• -malı / -meli = should / must
• -sın = you (singular)

So:

• yaklaşmalısın = you should approach
• yaklaşmamalısın = you should not approach

In natural English, this is often translated as you shouldn’t go near.

Not always.

The suffix -malı / -meli can express:

• advice: you should
• obligation: you must / have to
• strong recommendation or warning

In this sentence, yaklaşmamalısın sounds like a warning or safety advice: You shouldn’t go near trees when lightning flashes.

Depending on context, it can feel quite strong, but shouldn’t is usually a good translation here.

Because Turkish usually does not need subject pronouns when the verb already shows the person.

Here, -sın at the end of yaklaşmamalısın already tells us the subject is you (singular).

So:

• yaklaşmamalısın = you shouldn’t approach

You could say Sen ağaçlara yaklaşmamalısın, but that usually adds emphasis, contrast, or a stronger personal tone.

Turkish often puts time or condition expressions before the main action, and the main verb usually comes at the end.

So the sentence structure is:

• Şimşek çakınca = when lightning flashes
• ağaçlara = to trees
• yaklaşmamalısın = you shouldn’t approach

A very literal order would be:

When lightning flashes, to trees you-should-not-approach.

This is normal Turkish word order.

Yes, but the meaning shifts slightly.

• şimşek çakınca = when lightning flashes / whenever lightning flashes
• şimşek çakarken = while lightning is flashing

In this sentence, çakınca works very well because it gives a general when this happens meaning, which is common in warnings and instructions.

So Şimşek çakınca ağaçlara yaklaşmamalısın is very natural.

It can be both, but here it is clearly physical.

• physical: arabaya yaklaşmak = approach the car
• abstract: sona yaklaşmak = approach the end

In this sentence, because of ağaçlara, it clearly means physically getting close to trees.

Usually no, not in this sentence.

• yaklaşmak = to approach / get near
• yakınlaşmak often means to become closer, especially in a social or emotional sense

For example:

• Birbirlerine yaklaştılar = They moved closer to each other
• Zamanla yakınlaştılar = They became closer over time

For a safety warning about distance from trees, yaklaşmak is the correct verb.

You would usually say:

Şimşek çakınca ağaca yaklaşmamalısın.

Breakdown:

• ağaç = tree
• ağaca = to a tree

Notice the sound change:

• ağaç
  • -a
• becomes ağaca

This happens because the final ç becomes c before a vowel.

So:

• ağaçlara = to trees
• ağaca = to a tree

You would change the final person ending:

• yaklaşmamalısın = you shouldn’t approach (singular, informal)
• yaklaşmamalısınız = you shouldn’t approach (plural or polite singular)

So:

Şimşek çakınca ağaçlara yaklaşmamalısınız.

This can mean:

• you all shouldn’t go near trees
• or you shouldn’t go near trees in a polite/formal way

It usually sounds like general advice or a rule.

Şimşek çakınca often has a whenever this happens feeling, especially in warnings:

• Yağmur yağınca içeri gir. = Go inside when it rains.
• Şimşek çakınca ağaçlara yaklaşmamalısın. = You shouldn’t go near trees when lightning flashes.

So it is not only about one specific flash of lightning; it can easily mean a general safety rule.