Köpek kulübesi evin arkasında.

Because köpek kulübesi is a very common Turkish noun-compound pattern.

• köpek = dog
• kulübe = hut, kennel
• kulübesi = kennel + the compound/possessive ending

In Turkish, when one noun describes another noun like this, the first noun often stays bare, and the second noun takes a suffix:

• köpek kulübesi = dog kennel / kennel for a dog
• okul kapısı = school gate
• araba kapısı = car door

So köpek kulübesi is the normal way to say doghouse / kennel.

The -si here does not necessarily mean his/her/its in the ordinary sense. In compounds, it is just part of the standard structure.

Not really, even though the ending looks the same.

The ending in kulübesi is the same form as the 3rd person possessive suffix, but in a noun compound it often does not mean actual possession.

So in:

• köpek kulübesi

the meaning is simply doghouse / dog kennel, not necessarily the dog's kennel in the sense of a specific dog's personal possession.

If you wanted to say the dog's kennel, with a true possessor, you would usually say:

• köpeğin kulübesi

There, köpeğin is clearly of the dog / the dog's.

Because evin is in the genitive case, meaning something like of the house or the house's.

The expression evin arkasında literally works like:

• evin = of the house
• arkasında = at its back / behind it

So Turkish says behind the house using a structure that is closer to at the back of the house.

That is why ev becomes evin.

arkasında can be broken down like this:

• arka = back, rear
• -sı = its
• -nda = in/on/at, with a buffer n

So:

• arkası = its back / the back of it
• arkasında = at its back / behind it

Together with evin, you get:

• evin arkasında = behind the house

This is a very common Turkish pattern for location words such as:

• önünde = in front of
• arkasında = behind
• yanında = beside / next to
• üstünde = on top of
• altında = under

That n is a buffer consonant.

The locative ending is basically -da / -de. But when it comes after a possessive ending, Turkish often inserts n first:

• arkası
  • -da → arkasında

This happens in many similar forms:

• önü → önünde
• yanı → yanında
• üstü → üstünde

So the n helps connect the possessive form to the case ending smoothly.

Because of vowel harmony.

The locative suffix has different forms:

• -da
• -de
• -ta
• -te

The vowel changes depending on the last vowel before it. In arkasında, the relevant last vowel is ı, which belongs to the back-vowel group, so the suffix uses a:

• -da, not -de

The d/t choice depends on the preceding sound. Here the suffix comes after a vowel-plus-buffer situation, so d is used.

In Turkish, the present-tense to be is often not stated in simple sentences like this.

So:

• Köpek kulübesi evin arkasında.

naturally means:

• The doghouse is behind the house.

There is no separate word for is here.

Turkish often leaves it unspoken in the present tense with noun, adjective, and location predicates.

A more formal or emphatic version can use:

• Köpek kulübesi evin arkasındadır.

That still means the same thing, but sounds more formal, written, or definite.

Turkish often puts the most important statement at the end of the sentence.

Here:

• Köpek kulübesi = the topic / what we are talking about
• evin arkasında = the predicate / where it is

So the structure is very natural:

• Köpek kulübesi evin arkasında.

Literally, it feels like:

• The doghouse [is] behind the house.

Turkish word order is flexible, but this version is the most neutral here.

Yes, but the emphasis changes.

For example:

• Evin arkasında köpek kulübesi var.

This means something more like:

• There is a doghouse behind the house.

That sentence uses var, which is the usual way to say that something exists or is present somewhere.

Compare:

• Köpek kulübesi evin arkasında. = The doghouse is behind the house.
• Evin arkasında köpek kulübesi var. = There is a doghouse behind the house.

Both are natural, but they are structured a little differently.

Turkish does not have articles like English a/an and the.

Whether something is understood as definite or indefinite usually depends on:

• context
• word order
• whether the noun is marked in some way
• whether words like bir are used

In this sentence, köpek kulübesi can be understood from context as the doghouse or simply a doghouse, depending on the situation. In many textbook translations, English uses the doghouse because the sentence sounds like it is talking about a known object.

If you wanted to explicitly say a doghouse, you might use:

• bir köpek kulübesi

But Turkish often leaves that unmarked if the context is clear.

Not word-for-word, but it matches in meaning.

Turkish often expresses this idea with a possessed noun phrase:

• evin = of the house
• arkasında = at its back

So the literal sense is closer to:

• at the back of the house

But in normal English, we usually just say:

• behind the house

This is one of the common differences between Turkish and English structure: Turkish frequently uses forms like front, back, side, top, bottom as nouns with suffixes.

Yes. That is also possible and natural.

• arka = back
• taraf = side
• evin arka tarafında = at the back side of the house / behind the house

Compared with evin arkasında, it can sound a little more explicit or descriptive, but both are normal.

In everyday Turkish, evin arkasında is very common and simple.