Kız kardeşim gelince onu istasyonda karşılayacağım.

Yes. kardeş by itself means sibling. To specify a female sibling, Turkish uses kız kardeş, literally girl sibling.

Then the ending -im on kardeşim means my.

So:

• kardeş = sibling
• kardeşim = my sibling
• kız kardeşim = my sister

The possessive ending attaches to the second word of the expression.

gelince comes from:

• gel- = come
• -ince / -ınca = when, once, as soon as

So kız kardeşim gelince means when my sister comes/arrives.

This suffix is a very common way to make a time clause in Turkish. Instead of using a separate word like when, Turkish often adds a suffix to the verb.

It can cover all of those, depending on context.

In this sentence, gelince most naturally means something like:

• when she comes
• once she arrives
• as soon as she gets here

The exact English translation depends on how immediate the action feels in context.

No, not usually.

gelince points to the time of arrival or the moment the coming happens: when she comes or once she arrives.

If you want while she is coming, Turkish more often uses gelirken.

Compare:

• gelince = when/once she comes
• gelirken = while she is coming

Because onu is the direct-object form of o.

• o = she / he / it
• onu = her / him / it

In this sentence, my sister is the person being met at the station, so she is the direct object of karşılayacağım.

That is why Turkish uses onu, not o.

Sometimes yes, if the object is already obvious from context.

Turkish often leaves out words that can be understood. So something like Kız kardeşim gelince istasyonda karşılayacağım might be understood as I’ll meet her at the station when my sister comes.

But keeping onu is clearer and very natural. It makes the sentence more explicit.

Because istasyonda means at the station, while istasyona means to the station.

• istasyon = station
• istasyonda = at/in the station
• istasyona = to the station

Here the sentence tells you where the meeting will happen, so the locative ending -da / -de is used.

It breaks down like this:

• karşıla- = verb stem from karşılamak
• -yacak / -yecek = future marker after a vowel
• -ım / -im / -um / -üm = I

So:

karşıla + yacak + ım → karşılayacağım

There is also a sound change: the k in -acak softens to ğ before the personal ending, which is why you see -acağım.

So karşılayacağım means I will meet / receive / welcome.

Because Turkish usually shows the subject through the verb ending.

In karşılayacağım, the ending already tells you the subject is I. So a separate ben is not necessary.

You could say:

• Ben kız kardeşim gelince onu istasyonda karşılayacağım.

But ben would usually add emphasis, like I will meet her.

It is often more specific than plain meet.

karşılamak commonly means:

• to meet someone on arrival
• to receive someone
• to welcome someone

So in places like a station, airport, or doorway, karşılamak is a very natural verb.

If you simply mean meet up with someone, Turkish may use other verbs depending on context, such as buluşmak.

Not completely, but this order is very natural.

The sentence is arranged like this:

• Kız kardeşim gelince = when my sister comes
• onu = her
• istasyonda = at the station
• karşılayacağım = I will meet

Turkish often puts the main verb at the end, so karşılayacağım naturally comes last.

You can move parts around for emphasis, but the original order is a standard, neutral way to say it.