Sabah pazardan vişne aldım; vişneler biraz ekşi ama çok taze.

Yes. In Turkish, some time words can be used adverbially without a case ending, and sabah is one of them.

So:

• Sabah geldim. = I came in the morning.
• Sabah pazardan vişne aldım. = In the morning, I bought sour cherries from the market.

You may also hear fuller forms such as sabahleyin, but plain sabah is very common in everyday Turkish.

Because -dan / -den means from, while -da / -de means in / at.

• pazar = market
• pazarda = at the market / in the market
• pazardan = from the market

With verbs like almak (to buy), Turkish often marks the place you buy something from with the ablative ending:

• Marketten ekmek aldım. = I bought bread from the store.
• Pazardan vişne aldım. = I bought sour cherries from the market.

English often says at the market, but Turkish focuses on the source: from the market.

Because vişne here is an indefinite, non-specific object.

In Turkish:

• vişne aldım = I bought sour cherries / some sour cherries
• vişneleri aldım = I bought the sour cherries (specific ones)

A bare noun with no plural ending and no accusative ending often works like an indefinite object in Turkish. This is very common.

So vişne aldım does not mean only one cherry. It can mean some sour cherries in a general, indefinite sense.

Because in the second clause the speaker is now referring to those cherries as a specific set:

• vişneler biraz ekşi = the cherries are a little sour

So there is a shift:

1. vişne aldım → indefinite: I bought some sour cherries
2. vişneler biraz ekşi → now those cherries are being talked about specifically: the cherries are a bit sour

This is very natural in Turkish.

Because Turkish usually adds the accusative ending only to a definite/specific direct object.

Compare:

• Vişne aldım. = I bought some sour cherries.
  
  • indefinite / non-specific
• Vişneyi aldım. = I bought the sour cherry / the sour cherries depending on context
  
  • definite / specific

This is one of the biggest differences from English. English always needs an article or context to show definiteness, but Turkish often shows it through the accusative.

Aldım comes from the verb almak (to take / buy).

Breakdown:

• al- = verb stem
• -dı- = past tense
• -m = I

So:

• aldım = I bought / I took

The vowel changes because of vowel harmony and sound changes, so al + dı + m becomes aldım.

No. In Turkish, adjectives do not agree with the noun in number or person.

So:

• taze vişne = fresh sour cherry / fresh sour cherries
• taze vişneler = fresh sour cherries
• vişneler taze = the cherries are fresh

The adjective stays the same. This is much simpler than in many Indo-European languages.

They modify the adjectives in different ways:

• biraz ekşi = a little sour / somewhat sour
• çok taze = very fresh

So:

• biraz softens the description
• çok strengthens it

The whole sentence gives a natural contrast:

• they are a bit sour
• but very fresh

Yes. Ama means but, and it is very common in everyday speech.

You could also say:

• fakat = but / however
• ancak = but / however

But ama is the most conversational and natural here:

• Vişneler biraz ekşi ama çok taze.

So ama is a very normal choice.

Turkish often leaves out subject pronouns when the verb already shows who the subject is.

In aldım, the ending -m already means I. So:

• (Ben) sabah pazardan vişne aldım.
• Sabah pazardan vişne aldım.

Both mean I bought sour cherries from the market in the morning, but the second is more natural unless you want emphasis on I.

This is a very normal Turkish word order.

A rough pattern is:

time + place/source + object + verb

So:

• Sabah = time
• pazardan = source/place
• vişne = object
• aldım = verb

Turkish usually puts the verb at the end. That is one of its most important sentence patterns.

Other word orders are possible for emphasis, but this version is the most neutral and natural.

No. Vişne and kiraz are different.

• kiraz = sweet cherry
• vişne = sour cherry

So this sentence is specifically about sour cherries, which fits well with biraz ekşi (a little sour).

The semicolon links two closely related ideas:

1. Sabah pazardan vişne aldım
2. vişneler biraz ekşi ama çok taze

It works like: I bought sour cherries from the market this morning; they’re a little sour but very fresh.

A period would also be possible:

• Sabah pazardan vişne aldım. Vişneler biraz ekşi ama çok taze.

The semicolon just shows the ideas are tightly connected.