Lütfen televizyonun sesini biraz kıs.

A natural breakdown is:

• Lütfen = please
• televizyonun = of the television / the TV's
• sesini = its sound / its volume
• biraz = a little / a bit
• kıs = lower / reduce / turn down

So the sentence literally means something like Please lower the TV's sound a bit, which in natural English is Please turn the TV down a little.

Because Turkish is using a possessive structure: the TV's sound.

• televizyon = television
• televizyonun = the television's / of the television

The ending -un is the genitive suffix here. It marks televizyon as the possessor.

This is a very common Turkish pattern:

• arabanın kapısı = the car's door
• evin penceresi = the house's window
• televizyonun sesi = the TV's sound

So Turkish does not just say television sound here. It says the television's sound.

Because sesini contains two different pieces of grammar.

Start with:

• ses = sound, voice, noise

Then:

• sesi = its sound / the sound of it

Here, sesi has the 3rd person possessive ending -(s)I, because it belongs to televizyonun.

So:

• televizyonun sesi = the TV's sound

But in your sentence, this noun is also the direct object of the verb kıs. Since it is specific and definite, it takes the accusative ending too.

So:

• sesi
  • -ni = sesini

That n is a buffer consonant used after the possessive ending.

So the full structure is:

• televizyon-un ses-i-ni
• TV-GEN sound-POSS.3SG-ACC

In simpler English: the TV's sound as the thing being turned down.

Kıs is the 2nd person singular imperative of kısmak.

• kısmak = to reduce, to lower, to turn down, to cut back
• kıs = lower it / turn it down

In this sentence, it means turn down or lower the volume.

Turkish often uses kısmak for things like:

• müziği kıs = turn the music down
• sesi kıs = lower the sound
• ışığı kıs = dim the light

So kıs is a command addressed to one person.

Because Turkish often uses a single verb where English uses a verb + particle.

English says:

• turn down the TV

Turkish says:

• televizyonun sesini kıs

The idea of down/reduce/lower is already built into kısmak.

So you should not try to translate down word-for-word. The Turkish verb itself carries that meaning.

Literally, ses means sound, voice, or noise, depending on context.

In this sentence, televizyonun sesi most naturally means the TV's sound, and in practical English that usually comes out as the volume of the TV.

So in context:

• televizyonun sesini kıs = lower the TV's sound = turn the TV volume down

This is very natural Turkish.

Biraz means a little or a bit.

It does two things here:

1. It gives the literal meaning lower it a little, not completely.
2. It softens the request slightly.

Compare:

• Televizyonun sesini kıs. = Turn the TV down.
• Televizyonun sesini biraz kıs. = Turn the TV down a bit.

So biraz makes the request sound a little gentler and more specific.

Because it is modifying the action: lower it a little.

In Turkish, adverbs like biraz often appear before the verb, especially in simple sentences. So:

• televizyonun sesini biraz kıs

is a very natural word order.

Turkish word order is somewhat flexible, but the verb usually comes at the end, and this placement of biraz is standard and easy to understand.

Yes, it is polite enough in many everyday situations because of lütfen.

However, the verb form kıs is still a direct command, so it is most suitable for:

• friends
• family
• children
• people you speak to informally

If you want to sound more polite or formal, you could say:

• Lütfen televizyonun sesini biraz kısar mısın? = Could you turn the TV down a bit?
• Lütfen televizyonun sesini biraz kısar mısınız? = Could you turn the TV down a bit? (more polite/formal)
• Lütfen televizyonun sesini biraz kısın. = Please turn the TV down a bit. (polite imperative)

So the original sentence is polite, but not highly formal.

Yes. A very common shorter version is:

• Televizyonu biraz kıs.

This literally looks like lower the TV a bit, but in context it naturally means turn the TV down a bit.

Another short option, if the object is obvious, is:

• Sesini biraz kıs. = Turn its volume down a bit.

The full version televizyonun sesini biraz kıs is more explicit because it specifically mentions the TV's sound/volume.

That is a very common question.

The ı in kıs is the Turkish dotless i. It is not the same as English ee or ih.

A rough guide:

• kıs sounds somewhat like kuss, but with a shorter, flatter vowel
• the vowel is produced deep in the mouth, without rounding the lips

So:

• kis would be wrong
• kees would be wrong
• kıs has its own Turkish vowel sound

You do not need a perfect imitation right away, but it is worth practicing, because i and ı are different vowels in Turkish and can change meaning.