صدای تلویزیون خیلی بلند بود، برای همین مادرم آن را کم کرد.

It literally means the sound of the television or the TV’s sound.

This is a noun phrase built with ezafe:

• صدا = sound
• صدای = sound of ...
• تلویزیون = television / TV

So صدای تلویزیون = the sound/volume of the TV.

Because صدا ends in a long vowel, Persian adds a written ی before the ezafe sound, so it is read as sedâ-ye televizion.

Yes, بلند can mean tall, high, or loud, depending on context.

Here the context is sound:

• صدای بلند = loud sound / loud voice

So in this sentence, خیلی بلند بود means was very loud, not was very tall.

In Persian, the verb often comes at the end of the clause.

So:

• خیلی = very
• بلند = loud
• بود = was

Literally, the order is something like:

the TV’s sound very loud was

That is completely normal Persian word order.

برای همین means for this reason, so, or that’s why.

It connects the first clause to the result:

• The TV was very loud, so my mother turned it down.

It is a very common everyday way to show cause and result.

Both mean my mother.

• مادرم = my mother
• مادر من = my mother

The -م at the end is an attached pronoun meaning my.

In many cases, the attached form is more natural and compact in Persian:

• مادرم = my mother
• دوستم = my friend
• کتابم = my book

So مادرم is a very normal choice here.

آن means that or it here, and را marks the direct object.

So:

• آن = it / that
• را = direct object marker

Together, آن را means it as the thing being acted on.

In this sentence, آن را کم کرد means she reduced it / turned it down.

The marker را is used because the object is specific and definite.

It refers to the sound/volume of the television.

So even though English often says she turned the TV down, Persian is really talking about reducing the sound:

• صدای تلویزیون = the TV’s sound
• آن را کم کرد = she reduced it

So آن points back to the sound, not to the television set itself.

Because Persian, like English, often uses a pronoun to avoid repetition.

Instead of saying:

• مادرم صدای تلویزیون را کم کرد

the sentence says:

• مادرم آن را کم کرد

Both are correct. The version with آن را sounds smoother because it avoids repeating the full noun phrase.

Literally, کم کرد means made less or reduced.

• کم = less / low
• کرد = did / made

So کم کرد is a very common Persian verb phrase meaning reduced.

With sound or volume, it naturally means:

• turned down
• lowered

So آن را کم کرد = she turned it down.

Yes. It is an example of a very common Persian pattern where a non-verbal element combines with کردن to make a full verb.

Here:

• کم = less
• کردن = to do / to make

So کم کردن = to reduce / to lower / to turn down

This kind of structure is extremely common in Persian.

Yes. In everyday spoken Persian, you might hear something like:

• صدای تلویزیون خیلی بلند بود، برای همین مادرم اونو کم کرد.

Here:

• اونو = spoken form of آن را

In even more casual speech, someone might say:

• صدای تلویزیون خیلی بلند بود، برای همین مادرم صداشو کم کرد.

That literally means my mother lowered its sound.

خیلی means very here.

It comes before the adjective it modifies:

• خیلی بلند = very loud

This is the normal pattern in Persian:

• خیلی خوب = very good
• خیلی بزرگ = very big
• خیلی بلند = very loud

So خیلی is intensifying بلند.

The sentence breaks down like this:

• صدای تلویزیون = the TV’s sound / the sound of the TV
• خیلی بلند بود = was very loud
• برای همین = so / for this reason
• مادرم = my mother
• آن را = it
• کم کرد = turned it down / reduced it

So the literal structure is roughly:

The sound of the TV was very loud, so my mother reduced it.

And the natural English meaning is:

The TV was very loud, so my mother turned it down.