У рояля сидел пианист и медленно играл новую мелодию.

У + genitive often means by, near, or at something/someone.

So у рояля means by the piano / at the piano.

Here, it describes the pianist’s location. He is sitting near the grand piano, in the position of playing it.

A useful comparison:

• у рояля = by the piano, at the piano
• за роялем = seated at the piano, literally behind the piano from the player’s perspective

In many contexts, both can work, but у рояля is very natural for describing where someone is.

The dictionary form is рояль = grand piano.

After the preposition у, Russian normally uses the genitive case, so:

• рояль → рояля

This is a masculine noun, and the ending changes because of the case.

So:

• nominative: рояль
• genitive: рояля

That is why the sentence has у рояля.

Russian word order is flexible. Both are grammatically correct:

• Пианист сидел у рояля...
• У рояля сидел пианист...

The version in your sentence sounds a bit more descriptive or literary. It first sets the scene:

• У рояля = where?
• сидел пианист = who was there?

This kind of order is common when Russian introduces a setting first and then the person or thing in it.

So the meaning does not change much, but the emphasis does:

• Пианист сидел... = focus first on the pianist
• У рояля сидел пианист... = focus first on the scene/location

Both verbs are in the past tense, masculine singular form:

• сидел = was sitting / sat
• играл = was playing / played

Russian past tense agrees with gender and number:

• masculine: сидел
• feminine: сидела
• neuter: сидело
• plural: сидели

The subject is пианист, which is masculine singular, so the verbs are masculine singular too.

If the subject were feminine, for example пианистка, you would get:

• У рояля сидела пианистка и медленно играла новую мелодию.

Играл is imperfective. It presents the action as a process or ongoing activity:

• he was playing
• he played, in the sense of describing what he was doing

That fits the sentence well, because it paints a scene:

• he was sitting
• he was slowly playing a new melody

If you used сыграл, that would focus more on completion:

• сыграл новую мелодию = he played the new melody through / finished playing it

So:

• играл = process, background, duration
• сыграл = completed result

In this sentence, the speaker is describing the scene, not emphasizing completion, so играл is the natural choice.

Because мелодию is the direct object of играл. In Russian, direct objects usually go into the accusative case.

The dictionary form is:

• новая мелодия = a new melody

In the accusative singular, it becomes:

• новую мелодию

Both the adjective and the noun change to match each other:

• новая → новую
• мелодия → мелодию

So:

• играл новую мелодию = was playing a new melody

Russian has no articles. There is no direct equivalent of English a or the.

So пианист can mean:

• a pianist
• the pianist

And новую мелодию can mean:

• a new melody
• the new melody

Which one sounds best depends on context.

Russian usually shows definiteness through context, word order, or additional words if needed.

For example:

• этот пианист = this pianist
• какой-то пианист = some pianist
• эта новая мелодия = this new melody

But in your sentence, Russian simply leaves that to context.

Медленно is an adverb meaning slowly. It describes how he was playing.

In the sentence:

• и медленно играл новую мелодию

it modifies играл.

Yes, Russian allows some flexibility in adverb placement. For example:

• ...и медленно играл новую мелодию
• ...и играл новую мелодию медленно
• ...и новую мелодию играл медленно

These versions are all possible, but they may sound slightly different in emphasis.

The original order is very natural and neutral.

Yes. И means and, and here it connects two actions done by the same subject:

• сидел
• играл

The subject пианист applies to both verbs:

• the pianist was sitting
• the pianist was playing

Russian often does this exactly like English:

• Он сидел и читал. = He was sitting and reading.
• Пианист сидел и играл. = The pianist was sitting and playing.

So there is no need to repeat пианист.

It could, but that would express something slightly different.

Russian often uses:

• играть на рояле = to play the piano

But in your sentence, the object of играл is not the instrument. It is новую мелодию:

• he was playing a new melody

So the sentence already tells you what he was playing. The phrase у рояля gives the setting.

You could say:

• Пианист сидел за роялем и медленно играл новую мелодию.
• Пианист медленно играл новую мелодию на рояле.

Those are also correct, but the original sentence chooses a different structure: location first, then action.

This is a vocabulary question many learners have.

• рояль = grand piano
• пианино = upright piano

So у рояля specifically means the pianist is at a grand piano, not just any piano in general.

That can matter because рояль often sounds more formal, concert-like, or elegant.

In this sentence, was sitting is usually the better match.

The verb сидел is imperfective and describes a state or ongoing situation in the past. The sentence is painting a scene:

• he was sitting at the piano
• he was slowly playing a new melody

English sat is possible in some contexts, but here was sitting usually captures the Russian better.

So although сидел can sometimes translate as sat, in this sentence was sitting is the most natural choice.

Not necessarily. Играл новую мелодию simply means he was playing a melody that is new in the context.

That could mean:

• new to the listener
• newly learned
• newly written
• just introduced in the story

Russian does not automatically imply that he composed it. If the sentence wanted to make composition clear, it would usually say so more directly.

For example:

• играл свою новую мелодию = was playing his new melody
• сочинял новую мелодию = was composing a new melody

So the sentence itself only says he was playing a new melody, not that he wrote it.