Jag pratar inte om det här med vem som helst.

Because they do two different jobs:

• prata om något = talk about something
• prata med någon = talk with someone

So in:

Jag pratar inte om det här med vem som helst

you have both ideas at once:

• om det här = about this
• med vem som helst = with just anyone

A useful way to see the structure is:

Jag pratar inte [om det här] [med vem som helst].

So the sentence means: I don’t talk about this with just anyone.

In a normal Swedish main clause, the finite verb usually comes early, and inte typically comes after it.

So:

• Jag pratar inte ...

not

• Jag inte pratar ...

This is standard Swedish word order in main clauses.

Compare:

• Jag kommer inte. = I’m not coming.
• Hon vet inte. = She doesn’t know.

A useful contrast is with subordinate clauses, where inte often comes before the verb:

• ... att jag inte pratar om det här ... = ... that I do not talk about this ...

So in your sentence, Jag pratar inte ... is exactly what you should expect in a main clause.

det här means this.

In Swedish, det här is a very common way to say this when referring to a neuter thing, idea, situation, or topic.

Here it refers to this matter / this topic / this.

Literally:

• det = it / that
• här = here

But together, det här functions like this.

Examples:

• Det här är viktigt. = This is important.
• Jag gillar inte det här. = I don’t like this.

In your sentence, om det här means about this.

Yes, often it could, but the tone changes.

• det här is the common, everyday spoken form
• detta is more formal, written, or official

So:

• Jag pratar inte om det här med vem som helst. = natural everyday Swedish
• Jag pratar inte om detta med vem som helst. = more formal

Both are correct, but det här sounds much more natural in ordinary conversation.

vem som helst is a fixed expression meaning:

• anyone
• just anyone
• any random person

Literally, it is built from:

• vem = who
• som helst = roughly at all / you like / whatsoever in this kind of expression

So med vem som helst means:

• with just anyone
• with no matter who
• with any random person

This expression is very common in Swedish.

Similar patterns:

• vad som helst = anything
• när som helst = anytime
• var som helst = anywhere
• hur som helst = anyway / however

Because the meaning is stronger and more specific.

• med någon = with someone
• med någon som helst is not the normal wording here
• med vem som helst = with just anyone / with any random person

The sentence is not merely saying I don’t talk about this with someone. It means I am selective about who I talk to about this.

So vem som helst adds the idea of just any person at all.

They are similar, but pratar is more natural in everyday speech.

Both can mean speak or talk, but:

• prata = talk, speak; common and conversational
• tala = speak; often a bit more formal or neutral

So you could say:

• Jag pratar inte om det här med vem som helst.
• Jag talar inte om det här med vem som helst.

Both are understandable, but pratar sounds more natural in ordinary spoken Swedish.

Yes, Swedish allows some variation, but the original is very natural.

For example, you could say:

• Om det här pratar jag inte med vem som helst.

This puts extra focus on om det här.

But the original:

• Jag pratar inte om det här med vem som helst.

is the most straightforward, neutral version.

One thing to remember: if you move something to the front in Swedish, the verb still usually stays in second position. That is why:

• Om det här pratar jag inte ...

not

• Om det här jag pratar inte ...

It can refer to any of those, depending on context.

In this sentence, det här most naturally means:

• this topic
• this matter
• this issue
• this situation

Swedish often uses det här in a broad, flexible way, just like English this.

So even though the literal wording is simple, the actual reference depends on what the speakers are talking about.

It is mostly neutral to informal, and very natural in everyday speech.

Reasons:

• jag pratar is everyday spoken Swedish
• det här is also common spoken-style wording
• vem som helst is a standard idiomatic expression

So this sounds like something a person would naturally say in conversation.

A more formal version might be:

• Jag talar inte om detta med vem som helst.

But the original sentence is probably what you would hear more often in real life.

A very useful pattern is:

Jag pratar inte om X med Y.

meaning:

I don’t talk about X with Y.

You can swap in other words:

• Jag pratar inte om jobbet med mina barn. = I don’t talk about work with my children.
• Jag pratar inte om det här med alla. = I don’t talk about this with everyone.
• Jag pratar om politik med min bror. = I talk about politics with my brother.

So your sentence is a great example of how Swedish combines:

• subject: Jag
• verb: pratar
• negation: inte
• topic with om
• conversation partner with med