Yeğenim küçük anahtarlığı görünce onunla oynamak istedi.

Yeğenim means my niece or my nephew.

It is made of:

• yeğen = niece / nephew
• -im = my

So Turkish is using a possessive ending instead of a separate word like my.

Examples:

• yeğen = niece/nephew
• yeğenim = my niece/nephew
• yeğenin = your niece/nephew
• yeğeni = his/her niece/nephew

Turkish yeğen does not tell you the gender, so the sentence could refer to either a niece or a nephew.

Because Turkish often expresses possession by adding an ending directly to the noun.

So instead of saying something like my nephew, Turkish commonly says:

• yeğen-im = nephew/my-nephew

This is very normal in Turkish. The same pattern appears in many everyday words:

• annem = my mother
• babam = my father
• arkadaşım = my friend

So yeğenim is a very typical Turkish structure.

Because anahtarlığı is the direct object of the verb görünce (when seeing), and it is a specific object.

The base noun is:

• anahtarlık = keychain / key holder

Here it appears as:

• anahtarlığı

This includes the accusative marking used for a specific object. In simpler terms, it means the sentence is talking about the specific small keychain, not just a small keychain in general.

Compare:

• Küçük bir anahtarlık gördü. = He/she saw a small keychain.
• Küçük anahtarlığı gördü. = He/she saw the/that small keychain.

Also notice the final k changes to ğ before the vowel-ending suffix. That is a common sound change in Turkish.

This happens because of two things:

1. A suffix is added.
2. Final k often changes to ğ before a vowel in Turkish.

So:

• anahtarlık
  • object ending
• becomes anahtarlığı

This kind of change is very common:

• çocuk → çocuğu
• köpek → köpeği
• renk → rengi

So anahtarlığı is not a different word; it is just the suffixed form of anahtarlık.

Görünce means when (someone) saw or upon seeing.

It comes from:

• gör- = see
• -ünce / -ınca / -ince / -unca = when, once, upon doing

So:

• görünce = when he/she saw, when seeing

This ending is often called a converb or adverbial verb ending. It links one action to another:

• Eve gelince aradı. = When he came home, he called.
• Seni görünce sevindim. = When I saw you, I became happy.

In your sentence, görünce sets up the first action:

1. seeing the keychain
2. then wanting to play with it

Because this form usually does not mark the subject directly. The subject is understood from context.

In this sentence, the subject is yeğenim, so the natural reading is:

• Yeğenim ... görünce ... istedi.
• My niece/nephew, when he/she saw ..., wanted ...

So the same person is understood to be doing both actions:

• seeing
• wanting to play

Turkish often relies on context like this, especially in linked verb structures.

Onunla means with him, with her, or with it.

In this sentence, it most naturally means with it, referring to the keychain.

So:

• onunla oynamak = to play with it

This form is built from the third-person pronoun o plus the meaning with.

Common forms are:

• benimle = with me
• seninle = with you
• onunla = with him/her/it

Even though English distinguishes him / her / it, Turkish uses the same form, and context tells you which one is meant.

Yes, grammatically it could. Onunla can mean:

• with him
• with her
• with it

But in this sentence, the most natural reference is the small keychain, because the sentence has just mentioned it and play with it makes sense.

This is a common feature of Turkish: third-person pronouns are often context-dependent.

Oynamak istedi means wanted to play.

It is formed like this:

• oyna-mak = to play
• iste-di = wanted

Turkish often expresses want to do something with:

• verb infinitive + istemek

So:

• gitmek istiyorum = I want to go
• uyumak istiyor = he/she wants to sleep
• oynamak istedi = he/she wanted to play

This is a very important and common pattern.

Because the whole sentence is describing a past event.

• istedi = wanted

The ending -di is the common past tense marker in Turkish.

So the sequence is:

• he/she saw the keychain
• then he/she wanted to play with it

If it were present tense, it might be something like:

• oynamak istiyor = wants to play / is wanting to play

But here the event happened in the past, so istedi is used.

The sentence is:

• Yeğenim küçük anahtarlığı görünce onunla oynamak istedi.

A natural breakdown is:

• Yeğenim = my niece/nephew
• küçük anahtarlığı = the small keychain
• görünce = when seeing / when he/she saw
• onunla oynamak = to play with it
• istedi = wanted

So the overall structure is roughly:

My niece/nephew, when he/she saw the small keychain, wanted to play with it.

Turkish often puts the main finite verb at the end, so istedi comes last.

Because Turkish adjectives normally come before the noun they describe, just like in English.

So:

• küçük anahtarlık = small keychain
• büyük ev = big house
• güzel kitap = beautiful book

Also, Turkish adjectives do not change form for number or gender, so küçük stays küçük.

It can often mean either small or little, depending on context.

In this sentence, small is probably the most neutral translation:

• küçük anahtarlık = small keychain

But in other contexts, küçük can also mean:

• little
• young
• younger

Examples:

• küçük çocuk = little child / young child
• küçük kardeş = younger sibling

So the exact nuance depends on the noun and the situation.

It most commonly means keychain or key holder.

It is built from:

• anahtar = key
• -lık / -lik / -luk / -lük = a suffix that can create nouns meaning something related to, used for, or associated with the base word

So anahtarlık is literally something connected with keys.

Depending on context, it can mean:

• a keychain
• a key holder
• something used to keep or hang keys

In your sentence, keychain is the most natural meaning.

Because Turkish often uses verb endings instead of separate words for meanings like when, after, while, or by doing.

Here, the meaning when is built into görünce.

So instead of saying something like when he saw, Turkish can simply say:

• görünce

This is one reason Turkish sentences can look compact: a lot of meaning is packed into suffixes.

Yes. That is a very natural way to understand it.

Görünce can often be translated as:

• when seeing
• when he/she saw
• after seeing
• upon seeing

The best English choice depends on style and context. In this sentence, all of these are close in meaning.

Not with a separate pronoun, but the verb form and context make it clear.

• istedi = he/she wanted

Turkish often leaves out subject pronouns when they are already clear. Since yeğenim is already there, there is no need to add o.

So Turkish prefers:

• Yeğenim ... istedi.

rather than:

• Yeğenim ... o istedi.

The second version would usually sound unnecessary unless there is special emphasis.

Yes. That is a good literal-style translation.

A very close breakdown would be:

• Yeğenim = my niece/nephew
• küçük anahtarlığı = the small keychain
• görünce = upon seeing / when he/she saw
• onunla = with it
• oynamak = to play
• istedi = wanted

That kind of literal translation can be very helpful for understanding how the Turkish sentence is built.