Italian language

The Italian language was a language spoken on the planet Earth, predominantly spoken by Italians and in Italy.

A 17th century map from Earth labeled several locations in Italian, including the Indian Ocean (Mar di India) and the Bay of Bengal (Golfo de Bengala). (Star Trek: Enterprise, opening credits)

During a malfunction of the universal translator aboard USS Discovery caused by the Sphere lifeform, Commander Nhan's speech was translated into Italian: "Il traduttore universale no funziona." (DIS: "An Obol for Charon")

Nhan's statement translates to "The universal translator is not functioning," and was captioned as "Universal translator must be malfunctioning."

Spock asked Sybok "Qual sei tu?", translating as "Who art thou?" from Italian, when he initially didn't recognize his half-brother on Nimbus III in 2287. Sybok himself later used this phrase upon encountering an entity on Sha Ka Ree. (Star Trek V: The Final Frontier)

Leonardo da Vinci in the holodeck program created by Kathryn Janeway, as well as various others, occasionally spoke Italian:

Italian term/phase	English translation	Reference
Amici	Friends	VOY: "Concerning Flight"
Andiamo!	Let's go!	VOY: "Scorpion"
Benissimo	Very well	VOY: "Concerning Flight"
Bravo	Good	TOS: "I, Mudd", TNG: "The Nth Degree", "Ship In A Bottle", "Tapestry", "Frame of Mind", "Inheritance", VOY: "The Cloud", "The Thaw", "Revulsion", "The Disease", "Course: Oblivion", VOY: "Tinker Tenor Doctor Spy", "Workforce", "Human Error"
Buon giorno	Good day	VOY: "Concerning Flight"
Buffo	Funny	VOY: "Concerning Flight"
Buona sera	Good evening	VOY: "Scorpion"
Capisce	Understood?	DS9: "Tears of the Prophets", "The Siege of AR-558", "Badda-Bing, Badda-Bang"
Che bella!	Beautiful!	VOY: "Scorpion"
Che cazzo!	That fuck!	VOY: "Scorpion"
Che meraviglia!	Wonderful!	VOY: "Concerning Flight"
Esatto	Exactly	VOY: "Scorpion", "Concerning Flight"
Finito	Finished	VOY: "Concerning Flight"
Grazie	Thank you	VOY: "Concerning Flight"
Madonna mia!	My Lady!	VOY: "Concerning Flight"
Maestro	Teacher/Master	VOY: "Scorpion", "The Raven", "Concerning Flight", "Someone to Watch Over Me", "Virtuoso"; ENT: "Babel"
Meraviglioso!	Marvelous!	VOY: "Scorpion"
Momento	Moment	VOY: "Concerning Flight"
Scusi	Excuse me	VOY: "Scorpion", "Concerning Flight"
Signorina	Miss	VOY: "Scorpion", "Concerning Flight"
Signore/signori (plural)	Gentleman	VOY: "Concerning Flight"
Stupido animale	Stupid animal	VOY: "Concerning Flight"
Terremoto	Earth movement	VOY: "Concerning Flight"
Virtuoso	Virtue, or skill; a highly skilled singer	VOY: "Warhead"

Background information[]

The Star Trek: Voyager episode title "Virtuoso" is Italian, meaning virtuous or master.

The phrase used by Spock and Sybok is a quote from Dante's Divine Comedy.

The script for "The Siege of AR-558" misspelled "capisce" as "capice".