Misafirler gelince annem onları kapıda karşılıyor.

Gelince comes from the verb gelmek (to come / to arrive) plus the suffix -ince / -ınca, which often means when, once, or upon doing something.

So:

• gel- = come
• -ince = when / once

Together, gelince means when (they) come / when (the guests) arrive.

In this sentence, Misafirler gelince means When the guests arrive.

Because gelince is not the main verb of the sentence. It creates a time clause:

• Misafirler gelince = when the guests arrive
• annem onları kapıda karşılıyor = my mother greets them at the door

So gelince functions like when they come, not like a full standalone verb such as they are coming.

There are effectively two parts:

1. Misafirler gelince

   • subject: misafirler (the guests)

2. annem onları kapıda karşılıyor

   • subject: annem (my mother)

So the guests are the ones arriving, and my mother is the one greeting them.

This is very common in Turkish: a subordinate clause can have one subject, and the main clause can have a different subject.

Because -ince clauses do not normally take the same kind of personal endings that finite verbs do.

In other words, gelince itself does not need to show they. The subject is understood from misafirler.

So:

• Misafirler gelince = when the guests arrive
• not something like they-arrive-when with a separate plural marker on the verb

This is normal Turkish structure.

Because Turkish often shows possession with a suffix directly on the noun.

• anne = mother
• annem = my mother

The -m here means my.

This is why Turkish does not need a separate word like my in this sentence.

A few related forms:

• annem = my mother
• annen = your mother
• annesi = his/her mother

Because onları is the accusative-marked form, used here for a definite direct object.

• onlar = they
• onları = them

In this sentence, my mother greets them, so them is the direct object of karşılıyor.

Turkish often marks definite direct objects with the accusative. Since these are specific guests already mentioned, onları is the natural form.

Kapıda means at the door.

It is made from:

• kapı = door
• -da / -de = in / on / at

So:

• kapıda = at the door

This suffix changes according to vowel harmony and consonant voicing, so you may also see forms like evde, okulda, masada, etc.

Karşılıyor is from karşılamak (to greet / to meet / to welcome) and uses the -yor form.

• karşılıyor = is greeting / greets

In Turkish, the -yor form is very common and can be used not only for something happening right now, but also for:

• a repeated or usual action
• a vivid description of a scene
• something that happens whenever a certain situation occurs

So this sentence can naturally mean something like:

• When the guests arrive, my mother greets them at the door
• or My mother is greeting them at the door when the guests arrive, depending on context

In English, we often translate it with the simple present in this kind of when-clause sentence.

Not always. Karşılamak can mean several related things, depending on context, such as:

• to greet
• to welcome
• to meet
• sometimes even to receive

In kapıda karşılamak, it often suggests welcoming someone at the door.

So the idea is not just saying hello, but physically receiving the guests as they arrive.

No, Turkish word order is flexible, although some orders sound more neutral than others.

This sentence has a very natural order:

• Misafirler gelince = time clause
• annem = subject
• onları = object
• kapıda = location
• karşılıyor = verb

A very literal structure is:

When the guests arrive, my mother them at-the-door greets.

That said, Turkish can move parts around for emphasis. For example, kapıda could be placed earlier if you wanted to stress at the door. The verb usually stays at the end.

Because they play two different grammatical roles in two different clauses.

• In Misafirler gelince, misafirler is the subject of arrive.
• In annem onları kapıda karşılıyor, onları is the object of greets.

English does the same thing:

• When the guests arrive, my mother greets them at the door.

So this is not redundant; it is just normal grammar.

Yes, that is possible, but it is a slightly different structure.

• gelince = when / once they come
• geldiğinde = when they come / when they have come / at the time when they come

In many everyday contexts, both can be translated similarly. However:

• gelince often feels a bit more direct and event-based: when they arrive
• geldiğinde can feel a bit more like at the time that they arrive

For a learner, gelince is a very natural and common choice here.

It can be either, depending on context.

It might describe:

• a habitual action: Whenever guests arrive, my mother greets them at the door
• a specific scene: When the guests arrive, my mother greets them at the door

Turkish often leaves this kind of distinction to context, and the -yor form can work in both kinds of situations.