Adam köpeği dövmedi.

Because köpeği is the accusative form of köpek.

In this sentence, köpeği is the direct object and it refers to a specific dog, so Turkish uses the accusative ending.

The steps are:

• base noun: köpek = dog
• accusative suffix: -(y)I
• köpek + i would be expected, but Turkish often changes final k to ğ before a vowel
• so it becomes köpeği

So:

• köpek = dog
• köpeği = the dog / a specific dog (as the object)

This is the accusative case ending, used for a definite or specific direct object.

In this sentence:

• Adam = the man / a man
• köpeği = the dog (as the thing being beaten)

A very common contrast is:

• köpek = dog, a dog, dogs in a general or non-specific sense
• köpeği = the dog, or a particular dog already known/specific in context

So the accusative does not simply mean the in every situation, but it often signals that the object is specific.

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

That means a noun like adam can mean:

• a man
• the man

depending on context.

Likewise, köpeği usually suggests a specific dog, but Turkish does not use a separate word equivalent to English the.

So English must choose a or the when translating, but Turkish often leaves that to context and case marking.

Turkish shows this mainly through case marking and secondarily through word order.

In Adam köpeği dövmedi:

• Adam has no case ending here, so it is the subject
• köpeği has the accusative ending, so it is the object
• dövmedi is the verb: did not beat

So the structure is:

• Adam = the one doing the action
• köpeği = the one receiving the action

Even if English relies heavily on word order, Turkish often relies more on endings.

dövmedi can be broken down like this:

• döv- = beat
• -me- = negation
• -di = past tense

So:

• dövdü = he/she beat
• dövmedi = he/she did not beat

There is no extra ending here for he/she/it because in the 3rd person singular, Turkish often uses no personal ending in this tense.

Because Turkish usually makes verbs negative by adding a negative suffix directly to the verb.

So instead of:

• beat + not

Turkish does:

• döv- + me + di

This is very normal in Turkish:

• geldi = he/she came
• gelmedi = he/she did not come

So verbal negation is usually built inside the verb, not with a separate word.

Because of vowel harmony.

The negative suffix has two forms:

• -ma-
• -me-

After front vowels, Turkish generally uses -me-. After back vowels, it generally uses -ma-.

The verb stem döv- contains ö, which is a front vowel, so the correct form is:

• dövme-

Then with past tense:

• dövmedi

This is also due to Turkish sound patterns, especially vowel harmony and consonant voicing.

The past tense suffix has several forms:

• -dı
• -di
• -du
• -dü and after some voiceless sounds:
• -tı
• -ti
• -tu
• -tü

Here the vowel in the previous syllable is e, so the suffix uses i:

• -di

And since the negative suffix ends in a vowel (-me), the consonant appears as d, not t.

So:

• döv-me-di

Because Turkish often omits subject pronouns when they are not needed.

So instead of saying:

• O adam köpeği dövmedi

Turkish can simply say:

• Adam köpeği dövmedi

The subject is already clear from the noun adam, so no separate pronoun is necessary.

This is very common in Turkish.

It can mean either, depending on context.

By itself, adam does not force one interpretation. Turkish often leaves this open unless the wider context makes it clear.

So depending on the situation, this sentence could be understood as:

• The man did not beat the dog
• A man did not beat the dog

If the speaker and listener already know which man is being discussed, English would usually say the man.

That is normal in Turkish.

The subject of a sentence is usually in the basic form of the noun, with no special ending.
The direct object may take the accusative ending if it is definite or specific.

So here:

• adam = subject, basic form
• köpeği = object, accusative form

English does not mark this with endings, but Turkish often does.

Yes, it would sound different.

• Adam köpeği dövmedi = the man did not beat the / that specific dog
• Adam köpek dövmedi = the man did not beat a dog / dogs in a non-specific or generic sense

The version with köpeği points to a specific dog.
The version without the accusative sounds less specific.

This definite/non-definite object distinction is very important in Turkish.

Yes. Turkish word order is flexible, although subject-object-verb is the neutral order.

So this sentence in its basic order is:

• Adam köpeği dövmedi.

But Turkish can move parts around for emphasis:

• Köpeği adam dövmedi.
• Adam dövmedi köpeği. (less neutral, more marked)

The core meaning can stay similar because the endings show the roles, but the emphasis changes.

The most neutral version for learners is the original:

• Adam köpeği dövmedi.

Most basically, it means did not beat: a simple past negative.

Turkish -di is a past tense form, so the most direct translation is:

• did not beat

Sometimes English translation may vary a little depending on context, but for grammar purposes, this is the past tense negative.

Yes, in a sense.

Turkish verbs often already imply the person, and in the 3rd person singular there is often no visible ending beyond the tense marker itself.

So:

• dövmedim = I did not beat
• dövmedin = you did not beat
• dövmedi = he/she/it did not beat

So dövmedi naturally means he/she/it did not beat, depending on the subject.

In this sentence, the subject is adam, so we understand it as the man did not beat.

Because değil is usually used to negate nominal sentences, not ordinary action verbs.

For example:

• Adam doktor değil. = The man is not a doctor.

But with normal verbs, Turkish usually uses the negative suffix -ma/-me:

• Adam gelmedi. = The man did not come.
• Adam köpeği dövmedi. = The man did not beat the dog.

So with döv-, the correct negation is dövmedi, not döv değil.