Non rubare il telefono.

Because this is the negative informal singular imperative in Italian.

With tu commands:

• positive: Ruba! = Steal!
• negative: Non rubare! = Don’t steal!

So in this specific pattern, Italian uses non + infinitive.

It is addressed to one person, in an informal way.

So Non rubare il telefono is what you would say to:

• a friend
• a child
• someone you speak to as tu

Related forms:

• Non rubate il telefono = don’t steal the phone (to more than one person)
• Non rubi il telefono = don’t steal the phone (formal, Lei)

Non is the standard word for not in Italian. It usually goes before the verb.

Examples:

• Rubo = I steal
• Non rubo = I do not steal
• Rubare! = To steal! / Steal!
• Non rubare! = Don’t steal!

So here, non turns the command into a negative command.

Italian uses articles much more often than English does. So where English might sometimes say just phone, Italian often prefers il telefono.

Here:

• il = the
• telefono = phone / telephone

So il telefono literally means the phone.

Usually, yes. Il telefono normally suggests the phone, meaning a phone that is understood from the context.

For example:

• on a table in front of you: Non rubare il telefono
• talking about someone’s device that both speakers know about: Non rubare il telefono

If you wanted a more general idea, Italian might use:

• Non rubare telefoni = Don’t steal phones

The base form is rubare, which means to steal.

It is a regular -are verb.

A few forms:

• rubare = to steal
• rubo = I steal
• rubi = you steal
• ruba = he/she steals, or steal! (positive informal command)
• rubano = they steal

In this sentence, rubare appears in the infinitive because of the negative tu command pattern.

Yes, but it means something different.

• rubare = to steal
• prendere = to take

So:

• Non rubare il telefono = Don’t steal the phone
• Non prendere il telefono = Don’t take the phone

In some situations, take and steal may feel similar in English, but in Italian the verbs are not the same.

Not necessarily. Telefono can mean telephone or phone in a general sense.

If you want to be more specific, Italian also uses:

• cellulare = cell phone / mobile phone
• telefonino = mobile phone, often a bit more colloquial

So you could also hear:

• Non rubare il cellulare = Don’t steal the cell phone

A simple English-style guide is:

roo-BAH-reh

And the whole sentence:

non roo-BAH-reh eel teh-LEH-foh-no

A few notes:

• r is usually rolled or tapped in Italian
• e is always pronounced, never silent
• telefono has the stress on le: te-LE-fo-no

Yes, it is perfectly grammatical and natural. It sounds like a direct warning or command.

Depending on tone and situation, though, a speaker might also say something softer or more specific, such as:

• Non toccare il telefono = Don’t touch the phone
• Non prendere il telefono = Don’t take the phone
• Non rubargli il telefono = Don’t steal his/her phone

So Non rubare il telefono is correct, but the exact choice depends on what the speaker wants to emphasize.