Tato síť funguje.

Tato is the full demonstrative adjective meaning this.

• tato síť = this network / this net
• ta síť can also occur in real Czech, but it often sounds less neutral and can be more like that/that particular one depending on context, intonation, or style.

For a basic textbook sentence, tato is the clearest standard way to say this before a feminine noun in the nominative singular.

Síť is a feminine noun.

That is why it takes the feminine form tato.

Czech demonstratives and adjectives must agree with the noun in:

• gender
• number
• case

So:

• masculine: tento
• feminine: tato
• neuter: toto

Since síť is feminine, tato is the correct form.

It is in the nominative singular.

Why? Because síť is the subject of the sentence:

• Tato síť funguje. = This network works.

The subject of a basic Czech sentence is normally in the nominative.

Funguje is the 3rd person singular present tense form of the verb fungovat.

So:

• já funguji / funguju = I function
• ty funguješ = you function
• on/ona/ono funguje = he/she/it functions

Since síť is a singular noun and means it, Czech uses the 3rd person singular verb form:

• síť funguje = the network works

It can mean both, depending on context.

Common translations include:

• to function
• to work
• to operate

So Tato síť funguje could mean:

• This network functions
• This network works
• This network is working

In everyday English, This network works is often the most natural translation.

A helpful approximation is seet with a very soft final consonant.

A few details:

• í is a long ee sound.
• ť is a softened t sound, made with the tongue closer to the roof of the mouth than in normal English t.

So síť is not pronounced like plain sit. The long vowel matters, and the final ť is softer than an ordinary English t.

That mark shows palatalization: the consonant is pronounced in a softer way.

So:

• t = ordinary t
• ť = soft t

This is an important distinction in Czech spelling and pronunciation. In síť, the final consonant is specifically ť, not plain t.

Yes. Czech word order is more flexible than English.

The neutral order here is:

• Tato síť funguje.

But depending on emphasis, you could also hear:

• Funguje tato síť? = Does this network work?
• Síť funguje. = The network works.
• Tato funguje. = This one works. (if síť is understood from context)

Even though word order can change, the original sentence is the most straightforward neutral statement.

Yes.

• Síť funguje. = The network works / A network works / The network is working, depending on context.
• Tato síť funguje. = This network works.

Adding tato makes the noun more specific. It points to a particular network.

It can be used for both.

Síť is a broad word meaning:

• net
• network

Examples:

• rybářská síť = fishing net
• počítačová síť = computer network
• sociální síť = social network

So in Tato síť funguje, the exact meaning depends on context. It could be a computer network, a phone network, or another kind of network.

Because Czech does not need an extra verb here the way English sometimes does.

In English, we say:

• This network works.
• This network is working.

In Czech, funguje already contains the full finite verb meaning works / is functioning. There is no need for a separate word like is.

It is neutral standard Czech.

• tato is standard and correct
• síť funguje is a normal everyday phrase
• the whole sentence sounds natural in speech and writing

It does not sound especially formal or especially casual. It is just a clear, standard statement.