Я обернулся, когда услышал своё имя у входа.

Обернулся comes from обернуться, which usually means to turn around / look back. In this sentence, it describes a single completed action: the speaker heard the name and then turned around.

A few useful contrasts:

• обернулся = turned around once, completed action
• оборачивался = was turning around / used to turn around / turned around repeatedly
• повернулся = turned, but not necessarily around toward what was behind or calling him

So обернулся is a very natural choice for I turned around after hearing something.

The -ся ending is the reflexive marker. In many Russian verbs, it does not mean a literal English-style reflexive like himself. Instead, it is just part of the verb’s normal form.

Here:

• обернуть = to turn something
• обернуться = to turn around oneself

So Я обернулся means I turned around, not I turned myself in a literal English sense.

In Russian past tense, verbs agree with the subject in gender and number.

Since the subject is Я, the form depends on whether the speaker is male or female:

• male speaker: Я обернулся, когда услышал...
• female speaker: Я обернулась, когда услышала...

So this sentence suggests the speaker is male.

This is an aspect question.

• слышать / слышал = to hear, to be hearing, to have the ability to hear
• услышать / услышал = to hear something at a particular moment, to catch the sound

In this sentence, the meaning is I heard my name as a single event, so услышал is the natural choice.

Compare:

• Я слышал музыку. = I heard / could hear music.
• Я услышал своё имя. = I heard my name (at that moment).

Russian often omits a repeated subject when it is already clear.

So:

• Я обернулся, когда услышал своё имя...

naturally means:

• I turned around when I heard my name...

Russian does not need to repeat я in the second clause, because it is obvious that the same person did both actions.

You could say когда я услышал, but it is often unnecessary.

Свой is a special possessive word meaning one’s own. Russian often uses it when the possessor is the same as the subject of the clause.

Here the subject is я, so:

• своё имя = my own name

This is more natural than моё имя in this sentence.

A useful comparison:

• Я услышал своё имя. = I heard my own name.
• Я услышал моё имя. = possible, but less natural in this context

Russian strongly prefers свой when it refers back to the subject.

Because имя is:

• neuter
• singular
• in the accusative case

The verb услышал takes a direct object, so имя is in the accusative. Since имя is an inanimate neuter noun, its accusative form looks the same as the nominative here:

• nominative: имя
• accusative: имя

The possessive pronoun must match it:

• своё = neuter singular accusative/nominative form of свой

So:

• своё имя = correct agreement

У входа means by the entrance, near the entrance, or at the entrance.

The preposition у normally requires the genitive case.

So:

• вход = entrance
• у входа = by/near the entrance

Other examples:

• у двери = by the door
• у окна = by the window
• у дома = by the house

So входа is genitive because it follows у.

Most naturally, it describes where the name was heard — in other words, the speaker heard someone say his name from near the entrance or at the entrance.

So the idea is something like:

• he heard his name coming from the entrance area
• someone near the entrance called his name

Russian allows this kind of short location phrase without spelling everything out.

Because когда услышал своё имя у входа is a subordinate clause.

Russian normally separates subordinate clauses with commas:

• Я обернулся, когда услышал своё имя у входа.

This is similar to English I turned around when I heard my name at the entrance, though English punctuation is often less strict here. In Russian, the comma is required.

No, Russian word order is fairly flexible, though each version can sound slightly different in emphasis.

The given sentence is neutral and natural.

Possible variations:

• Когда я услышал своё имя у входа, я обернулся.
• Я обернулся, когда у входа услышал своё имя.

These are grammatical, but the original is the most straightforward.

Russian word order often changes focus rather than basic meaning.

Here когда is best understood as when.

The sentence describes one action happening after another:

1. he heard his name
2. he turned around

So when fits better than while.

• Я обернулся, когда услышал... = I turned around when I heard...

If the sentence were emphasizing an ongoing simultaneous action, Russian would usually structure it differently.

Because Russian past tense agrees with the subject, the verb forms would change.

Female speaker:

• Я обернулась, когда услышала своё имя у входа.

Multiple speakers:

• Мы обернулись, когда услышали свои имена у входа.

Notice the changes:

• обернулся → обернулась / обернулись
• услышал → услышала / услышали
• своё имя → свои имена if multiple people heard their own names

The main stresses are:

• Я оберну́лся
• когда́
• услы́шал
• своё
• и́мя
• у вхо́да

A learner may especially want to notice:

• оберну́лся — stress on -ну́-
• услы́шал — stress on слы́
• своё — stress on the final -ё, which is always stressed

If you pronounce ё, that helps make своё clearer.