Hediye çeki birincilik ödülüydü.

A useful breakdown is:

• hediye = gift
• çeki = voucher / check / certificate
• birincilik = first place / first rank
• ödülüydü = was the prize / was its prize structure with past to be

So the sentence is built as:

• Hediye çeki = gift voucher
• birincilik ödülüydü = was the first-place prize

In other words, it is a noun phrase + noun phrase + past copula.

Because Turkish often does not use a separate verb like English to be in these kinds of sentences.

In Turkish:

• present tense often has no visible copula
  
  • Hediye çeki birincilik ödülü. = The gift voucher is the first-place prize.
• past tense adds a suffix meaning was/were
  
  • Hediye çeki birincilik ödülüydü.

So English uses a separate word (was), but Turkish usually attaches that meaning to the end of the predicate.

-ydü is the past form of the copula, meaning something like was.

Here it is attached to ödülü:

• ödülü + ydü → ödülüydü

This tells you the sentence is in the past:

• birincilik ödülü = the first-place prize
• birincilik ödülüydü = was the first-place prize

So -ydü is doing the job of English was.

Because the word it attaches to, ödülü, ends in a vowel.

In Turkish, when a suffix beginning with a vowel-like element is added after another vowel, a buffer consonant is often used to make pronunciation smoother. Here that buffer is y.

So:

• after a consonant: you may get forms like -di / -dı / -du / -dü
• after a vowel: you get -ydi / -ydı / -ydu / -ydü

Since ödülü ends in a vowel, Turkish uses -ydü.

This is because of vowel harmony.

The vowel in the suffix changes to match the last vowel of the word it attaches to. The last vowel in ödülü is ü, so the suffix also takes ü:

• ödülü + ydü

That is why you get ödülüydü.

These are very common in Turkish noun compounds.

Both hediye çeki and birincilik ödülü are compound noun phrases:

• hediye çeki = gift voucher
• birincilik ödülü = first-place prize

In this pattern, the first noun usually stays bare, and the second noun takes a suffix often called the third-person possessive ending:

• çek → çeki
• ödül → ödülü

Even though this suffix is historically possessive, in compounds it often just helps form a fixed meaning, not a literal possession like his/her.

So:

• hediye çeki does not mean his gift check
• birincilik ödülü does not mean his first-place prize

They are just standard compound structures.

Birincilik means first place, being first, or first rank.

It is built from:

• birinci = first
• -lik / -lık / -luk / -lük = a suffix that makes nouns

So:

• birinci = first
• birincilik = first-place status / first rank / championship-type idea

Then:

• birincilik ödülü = prize for first place

This is slightly different from just saying birinci ödül, which would be closer to first prize.
Birincilik ödülü emphasizes that the prize belongs to the achievement of coming first.

In Turkish nominal sentences like this one, both parts can appear without a special case ending, so context and position help.

Here the usual reading is:

• Hediye çeki = topic / subject
• birincilik ödülüydü = predicate

Turkish often puts the predicate at the end, so the last part is naturally understood as what the subject was.

So the structure is:

• The gift voucher
  • was the first-place prize

In some contexts, the reverse interpretation might be theoretically possible, but this sentence strongly suggests that the gift voucher is what is being identified.

Yes, Turkish word order is flexible, but changing it changes the emphasis.

The neutral order here is:

• Hediye çeki birincilik ödülüydü.

A different order could be used for emphasis, contrast, or style, for example putting focus on the prize part. But the version you have is the most straightforward and natural way to present the information.

So learners should treat this sentence as the normal, unmarked order.

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

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

• context
• word order
• whether the noun is specific
• the wider conversation

So:

• hediye çeki can mean a gift voucher or the gift voucher
• birincilik ödülü can mean a first-place prize or the first-place prize

In this sentence, the overall meaning usually makes it definite in English, so it is often translated with the.

It could be, but the most natural plain present-tense version is usually:

• Hediye çeki birincilik ödülü.

Turkish often uses a zero copula in the present, especially in everyday style.

The form with -dır / -dir / -dur / -dür is more formal, more emphatic, or more assertive:

• Hediye çeki birincilik ödülüdür.

So:

• ...ödülü. = is the first-place prize
• ...ödülüdür. = is the first-place prize, with a more formal or assertive tone
• ...ödülüydü. = was the first-place prize

Yes, it is a common compound meaning something like:

• gift voucher
• gift certificate
• gift check

Turkish often forms these kinds of expressions with noun compounds rather than separate words like English sometimes does.

So it is best to learn hediye çeki as a unit, not as two fully independent words each time you see it.

No special case ending is being used here beyond the compound structure endings.

Both main parts are in the basic dictionary form of the sentence:

• hediye çeki
• birincilik ödülüydü

This is typical for sentences of identification, where one thing is being equated with another:

• X, Y idi/ydi = X was Y

So this is not an accusative, dative, or locative pattern. It is a simple A was B sentence.

A rough pronunciation guide is:

• Hediye ≈ heh-dee-yeh
• çeki ≈ cheh-kee
• birincilik ≈ bee-rin-jee-lik
• ödülüydü ≈ uh-duh-luu-y-duu

A few useful points:

• ç sounds like ch
• ö is like the vowel in German schön or French peu, not a normal English o
• ü is like German ü or French u
• y in ödülüydü is clearly pronounced; it links the vowels smoothly

So the last word is not collapsed into one messy sound. You really do hear the linking y.