plurilinguismo:

Italian comes from Latin and nowadays in the Italian language there are still phrases and idioms that come from Latin and that are widely used, either in their original Latin form or in their modern translation.

• Ad litteram – Alla lettera: to the letter. Generally heard in the Italian form.
• Alea iacta est – Il dado è tratto: the die is cast, the famous phrase attributed to Caesar while crossing the Rubicone river and declaring war to the senate. We generally use the translation, but the original form is just as famous.
• Alma mater – Madre che nutre: nurturing mother. Many universities in Italy are called Alma Mater, the most famous of which is the University of Bologna, called Alma Mater Studiorum
• Carthago delenda est – Cartagine dev’essere distrutta: Carthage must be destroyed.
• Cum grano salis – Con un grano di sale: with a grain of salt, Pliny the Elder, both versions are used
• Cui prodest? – A chi giova?: who benefits from it?, Seneca. Both versions are used, but I’d say that the Latin form is more used, for example in detective stories
• Do ut des – Do perché tu mi dia: I give to you so that you give to me. The Italian translation is generally never used.
• Dura lex sed lex – Dura è la legge, ma è la legge: The law is hard/strict, but it’s the law
• Horror vacui – Orrore del vuoto: the horror of the void. Not widely used, but commonly known
• In medias res – Nel mezzo delle cose: in the middle of things, used to talk about books that start in the middle of the story
• In medio stat virtus – La virtù sta in mezzo (a due cose): virtue stands in between (two things), an invitation to moderation
• In vino veritas – Nel vino la verità: in the wine, there is truth. Funny answer recently added: “in vino veritas e in scarpe adidas” (in vino veritas and in shoes adidas)
• Labor limae – Lavoro di lima: smoothing out the details (lit. work of file), Horace. Both forms are known
• Lapsus linguae – Un errore della lingua: a mistake of the language/tongue. Generally used only in the form of “lapsus”, word that has entered the Italian dictionary
• Non plus ultra: ultimate/top object. The phrase has entered the Italian vocabulary as it is.
• Pecunia non olet – Il denaro non puzza: money doesn’t stink. Generally, the Latin form is used
• Sic semper tyrannis – Così sempre ai tiranni: lit. as always to the tyrants, the phrase usually attributed to Brutus after stabbing Ceasar.
• Sic transit gloria mundi – Così passa la gloria del mondo: this way passes the glory of the world.
• Tu quoque Brute, fili mi – Anche Tu Bruto, Figlio mio: Et tu Brute. In the English-speaking world, “Et tu Brute” is more used because it was used by Shakespeare in Julius Caesar. In Italy, on the other hand, we use “Tu quoque(..)”
• Vox populi vox dei – Voce del popolo, voce di Dio: voice of the people, voice of God. Usually used only as “vox populi”

I’m sure I forgot to add plenty of phrases but there are literally hundreds of these that are either famous and known or even used in everyday life.