Nefes desteği için diyafram kullanılır.

A natural breakdown is:

• nefes desteği = breath support
• için = for
• diyafram = diaphragm
• kullanılır = is used / one uses

So the literal order is roughly:

For breath support, the diaphragm is used.

Turkish often puts the verb at the end, so that final kullanılır is completely normal.

Because için is a postposition, not a preposition.

English says for breath support. Turkish says breath support for → nefes desteği için.

That is very common in Turkish:

• senin için = for you
• okul için = for school
• nefes desteği için = for breath support

It is an indefinite noun compound, a very common Turkish structure.

In English, we often put two nouns together directly:

• breath support
• coffee cup
• car door

In Turkish, this type of structure usually works like this:

noun + noun-(s)I

So:

• nefes desteği = breath support
• kahve fincanı = coffee cup
• araba kapısı = car door

The second noun gets a special ending, usually called the 3rd person possessive suffix, even though in English we often just translate it as a simple noun+noun phrase.

Because the second noun in this compound takes a suffix.

The base word is destek = support.

In the compound, it becomes:

destek + -(s)I → desteği

Two things happen:

1. It gets the compound/possessive ending.
2. The final k softens to ğ before a vowel-initial suffix.

So:

• destek → desteği

This softening is very common in Turkish:

• renk → rengi
• köpek → köpeği
• destek → desteği

Because nefes desteği and nefesin desteği are different structures.

• nefes desteği = breath support
  This is a general noun compound: a type of support.

• nefesin desteği = the breath’s support / the support of the breath
  This sounds more specific and more literally possessive.

In this sentence, the general concept breath support is what is meant, so nefes desteği is the natural form.

Kullanılır is the aorist passive form of kullanmak = to use.

Very roughly:

• kullan- = use
• -ıl- = passive
• -ır = aorist/general-habitual ending

So kullanılır means something like:

• is used
• gets used
• one uses

In this sentence, it gives a general, instructional, or factual tone. It sounds like the kind of sentence you might see in teaching, explanation, or technical writing.

Because Turkish passive sentences often cover both ideas.

Diyafram kullanılır can mean:

• The diaphragm is used
• One uses the diaphragm

English often chooses between a passive sentence and a generic subject like you, we, or one. Turkish often just uses the passive and leaves the agent unstated.

That makes the sentence sound general and impersonal, which fits this context well.

Because in this sentence diyafram is the subject of the passive verb, not the direct object.

Compare these:

• Nefes desteği için diyafram kullanılır.
  = The diaphragm is used for breath support.
  Here diyafram is the thing being used, so in the passive sentence it is the subject.

• Nefes desteği için diyaframı kullanırız.
  = We use the diaphragm for breath support.
  Here diyaframı is the direct object, so it takes the accusative ending.

So the lack of -ı here is correct.

Turkish does not have articles like English a/an/the.

A bare noun can be understood from context as:

• general
• definite
• indefinite

So diyafram can naturally correspond to the diaphragm in English, especially in an anatomical or instructional context.

English needs the article; Turkish usually does not.

Yes, both are natural.

Turkish word order is flexible, although the verb usually stays at the end.

• Nefes desteği için diyafram kullanılır.
  This puts the purpose first: for breath support...

• Diyafram nefes desteği için kullanılır.
  This puts diyafram first, so it feels a bit more like the topic.

Both are correct. The original sentence is perfectly natural, especially if the speaker wants to emphasize the purpose first.

Because kullanılır expresses a general fact, rule, or habitual usage.

• kullanılır = is used / one uses / is generally used
• kullanılıyor = is being used / is currently being used / is in use

So:

• Nefes desteği için diyafram kullanılır.
  = a general statement

• Şu anda nefes desteği için diyafram kullanılıyor.
  = right now, the diaphragm is being used / is being employed

For an explanatory sentence like this, kullanılır is the better choice.

The important thing is: ğ is usually not pronounced like a hard English g.

In desteği, many speakers pronounce it roughly like:

• des-te-i
• or des-te-yi

with a very soft transition.

So do not say a strong g sound like des-te-gi.

A rough full-sentence pronunciation might be:

NEH-fes des-TE-yi ee-CHIN dee-yaf-RAM kuhl-lah-nuh-LUHR

That is only an approximation, but it points you in the right direction.