Deşifre sırasında solist partisyonu izledi.

That is a very natural question. Deşifre can mean deciphering in a general sense, but in a music context it often means sight-reading.

Because the sentence also contains solist and partisyon, the musical meaning is the likely one here.

So in this sentence, deşifre sırasında is best understood as during sight-reading.

Sırasında means during in this kind of phrase.

The pattern is:

• X sırasında = during X

Examples:

• ders sırasında = during class
• konser sırasında = during the concert
• deşifre sırasında = during sight-reading

Historically, sırasında comes from sıra, but as a learner, the most useful thing is to treat X sırasında as a common set expression meaning during X.

Because in this pattern, the first word usually stays in a bare noun form.

So Turkish says:

• deşifre sırasında
• toplantı sırasında
• yemek sırasında

not something like an English-style during of X structure.

You can think of deşifre sırasında as a fixed noun phrase meaning during the sight-reading process/event.

The -u is the accusative ending, which often marks a specific, definite direct object in Turkish.

So:

• partisyon = a score / score in a general sense
• partisyonu = the score / a specific score

In this sentence, the soloist followed a particular score, so the object is marked.

Also, the form is -u because of vowel harmony:

• base word: partisyon
• accusative: partisyonu

This is a key Turkish grammar point.

• partisyon izledi = followed a score / score material in a less specific, more indefinite sense
• partisyonu izledi = followed the score, a specific one

English usually uses articles like a and the for this, but Turkish often shows the difference through object marking.

So the -u in partisyonu is doing important work.

İzledi is the simple past tense, third person singular.

It breaks down like this:

• izle- = verb stem, from izlemek
• -di = past tense
• third person singular has no extra ending here

So izledi means:

• he/she watched
• he/she followed

Because the subject is solist, the meaning is the soloist followed/watched.

Yes. İzlemek often means to watch, but it can also mean to follow, especially in contexts like:

• following a text
• following a route
• following music
• following a score or notation

So in this sentence, partisyonu izledi is not just physically looking at it. It more naturally means the soloist followed the score.

Because it is the subject of the sentence, and Turkish subjects are usually in the unmarked nominative form.

So:

• solist = the soloist / a soloist

No special ending is needed just because it is the subject.

By contrast, the object partisyonu does get a marking, because it is a specific direct object.

Mainly because of the endings and the verb structure.

• solist has no object marking, so it fits naturally as the subject
• partisyonu has the accusative ending, so it is the direct object
• izledi is a transitive verb here, so something is being followed

So the structure is:

• Deşifre sırasında = time expression
• solist = subject
• partisyonu = object
• izledi = verb

Yes, this is a very natural order.

Turkish commonly puts the verb at the end, and often places time expressions near the beginning. So this sentence follows a very typical pattern:

• Time expression
  • subject
    • object
      • verb

Here that is:

• Deşifre sırasında
  • solist
    • partisyonu
      • izledi

Turkish word order can change for emphasis, but this version sounds neutral and standard.

Not in the same way English does.

Turkish usually does not use articles like a and the before nouns. Instead, it often shows the difference through:

• context
• word order
• case endings

In this sentence:

• solist could mean the soloist or a soloist, depending on context
• partisyonu strongly suggests the score because the accusative marks it as a specific object

So Turkish often expresses what English articles express, but by different means.