Torunlar dikkatsiz koşunca babaanne onları yavaş yürümeleri için uyardı.

Koşunca comes from the verb koşmak (to run).

It is:

• koş- = verb stem, run
• -unca / -ince / -unca / -ünce = a suffix meaning when, once, or sometimes because/as soon as

So koşunca means when they ran or when the grandchildren ran.

In this sentence, the subject is already given as torunlar, so Turkish does not need to repeat they inside koşunca.

Yes, dikkatsiz is basically an adjective meaning careless, inattentive, or reckless.

But in Turkish, adjectives can often function adverbially without any extra ending. So:

• dikkatsiz çocuklar = careless children
• dikkatsiz koşmak = to run carelessly

So in Torunlar dikkatsiz koşunca, dikkatsiz describes how they ran: carelessly / without paying attention.

Torunlar means grandchildren.

It is:

• torun = grandchild
• -lar = plural suffix

So:

• torun = grandchild
• torunlar = grandchildren

There is no separate word for the here. Turkish often leaves definiteness to context, so torunlar can naturally mean the grandchildren if the context already makes that clear.

Babaanne specifically means paternal grandmother — your father’s mother.

Turkish distinguishes:

• babaanne = father’s mother
• anneanne = mother’s mother

English usually just says grandmother, unless the distinction matters.

So in this sentence, babaanne is more specific than English grandmother.

Because onları is the accusative/direct object form.

• onlar = they
• onları = them

In this sentence, the grandmother is warning them, so the pronoun is the object of uyardı (warned).

This is very common in Turkish:

• onlar geldi = they came
• onları gördüm = I saw them

Here:

• babaanne = subject
• onları = direct object
• uyardı = verb

This is a very common learner question.

Yürümek için usually means in order to walk in a general sense.

But yürümeleri için means so that they walk / for them to walk. It includes a specific understood subject: they.

Breakdown:

• yürü- = walk
• -me = verbal noun/infinitive-like element
• -leri = here it marks a third-person plural possessor/subject-like relationship
• için = for / in order to

So:

• yavaş yürümek için = in order to walk slowly (more general)
• yavaş yürümeleri için = for them to walk slowly

Since the grandmother is warning the grandchildren, Turkish uses the form that reflects that intended subject.

İçin often means for or in order to.

In this sentence, it introduces the purpose or content of the warning:

• yavaş yürümeleri için uyardı = warned them to walk slowly
• more literally: warned them for their walking slowly

This structure is very common in Turkish when one person tells, asks, advises, or warns another person to do something.

Examples:

• Erken gelmesi için onu aradım. = I called him so that he would come early.
• Sessiz olmaları için çocukları uyardı. = She warned the children to be quiet.

Yes. Yürümeleri can look complicated, but it is a standard Turkish structure.

It contains:

• yürü- = walk
• -me = verbal noun marker
• -leri = third-person plural possessive ending

So literally it is something like their walking.

In yavaş yürümeleri için, the phrase means:

• for them to walk slowly
• literally: for their walking slowly

Turkish often uses this kind of possessed verbal noun where English would use a clause with to.

Because Turkish normally places the conjugated main verb at the end of the sentence.

So the structure is:

• Torunlar dikkatsiz koşunca = when the grandchildren ran carelessly
• babaanne onları yavaş yürümeleri için = grandmother them for walking slowly
• uyardı = warned

This final-verb pattern is one of the most basic features of Turkish word order.

English: Grandmother warned them to walk slowly.
Turkish: Babaanne onları ... uyardı.

Uyardı comes from uyarmak, meaning to warn.

Breakdown:

• uyar- = warn
• -dı = past tense (did / -ed)

So uyardı means he/she warned.

Turkish often does not need a separate subject pronoun like she, because the subject is already present as babaanne.

Turkish usually does not translate English to + verb directly with one single equivalent.

Instead, it often uses:

• infinitives like -mek / -mak
• verbal nouns like -me / -ma
• plus other words such as için, gerekiyor, istemek, söylemek, uyarmak, etc.

So English warned them to walk slowly becomes Turkish onları yavaş yürümeleri için uyardı.

That is a very natural Turkish pattern, even though it looks structurally different from English.

Yes, but the meaning would change slightly.

• koşunca = when they ran / when they started running / since they ran
• koşarken = while they were running

So:

• Torunlar dikkatsiz koşunca... focuses on the situation when they ran carelessly, often with a sense of consequence.
• Torunlar dikkatsiz koşarken... would mean while the grandchildren were running carelessly...

In this sentence, koşunca works well because it sets up the reason or trigger for the grandmother’s warning.

Because the sentence refers to more than one grandchild.

• torunlar = grandchildren
• yürümeleri = their walking / for them to walk

The plural meaning is carried over into the embedded action as well. The ones who should walk slowly are the same plural people: the grandchildren.

In English, we do this with a pronoun:

• The grandchildren ... warned them to walk slowly

In Turkish, the plural is also reflected in the verbal-noun phrase:

• yürümeleri

It can sometimes be omitted if the object is completely clear from context, but here onları is very natural and helpful.

With uyarmak, Turkish often states the person being warned explicitly:

• Babaanne onları uyardı. = Grandmother warned them.

In this sentence, keeping onları makes the meaning clear and smooth:

• who did the warning? babaanne
• whom did she warn? onları

So while Turkish often drops things that are understood, this pronoun is very normal here.

A simple way to read it is:

1. Torunlar dikkatsiz koşunca
   = When the grandchildren ran carelessly

2. babaanne onları
   = grandmother [warned] them

3. yavaş yürümeleri için
   = to walk slowly

4. uyardı
   = warned

So the full pattern is:

[When-clause] + [subject] + [object] + [purpose/content phrase] + [main verb]

That is a very typical Turkish way to build a sentence.