The native language of the Carthaginians was Punic, a Northwest Semitic language derived from Phoenician. It was written using the Punic alphabet, a form of the Phoenician alphabet. "Berber" languages were definitely spoken by the various Amazigh peoples who lived in territories under Carthaginian control, but the Carthaginians themselves spoke Punic.

There are some surviving inscriptions written in the Punic language. For more information on Punic inscriptions, you can consult Karel Jongeling and Robert M. Kerr's book Late Punic Epigraphy: An Introduction to the Study of Neo-Punic and Latino-Punic Inscriptions, published by Mohr Siebeck in 2005.

A very strange additional literary attestation of the Punic language also occurs in the comedy Poenulus, written in the Latin language, most likely at some point between 195 and 189 BCE, by the Roman playwright Titus Maccius Plautus (lived c. 254 – c. 184 BCE). At the beginning of Act V of the comedy, the character Hanno comes on stage to deliver a poetic monologue in Punic, a translation of it into a second language that scholars disagree on the identity of, and then a translation of the monologue into Latin. The Punic text reads as follows, in F. Leo's edition:

"Yth alonim ualonuth sicorathi symacom syth
chy mlachthi in ythmum ysthyalm ych-ibarcu mysehi
li pho caneth yth bynuthi uad edin byn ui
bymarob syllohom alonim ubymysyrthohom
byth limmoth ynnocho thuulech-antidamas chon
ys sidobrim chi fel yth chyl is chon chen liful
yth binim ys dybur ch-innocho-tnu agorastocles
yth emanethi hy chirs aelichot sithi nasot
bynu yid ch-illuch ily gubulim lasibithim
bodi aly thera ynnynu yslym min cho-th iusim."

The Punic language continued to be spoken in many regions of North Africa previously controlled by the Carthaginian Empire even after the Romans conquered those regions, although it carried much lesser linguistic prestige than Latin and Greek. The North African writer Lucius Apuleius Madaurensis (lived c. 124 – c. 170 CE), who was very well educated and wrote very polished Latin, famously seeks in his Apologia 98.8–9 to portray his stepson, who was accusing him of having used evil magic to seduce his mother, as willfully ignorant by claiming that he only speaks Punic and not a word of Latin.

The Epitome de Caesaribus 20.8, an anonymous narrative covering the reigns of various Roman emperors probably written in the late fourth century CE, even claims that the Roman emperor Septimius Severus (ruled 193 – 211 CE), who was born in the town of Leptis Magna on the northern coast of what is now Libya, spoke Punic as his native language. The Historia Augusta v. Septimius Severus 15.7, a partly fictional account of the life of Septimius Severus most likely written in the late fourth or early fifth century CE, also claims that the emperor was embarrassed when his sister came to Rome and could only speak Punic fluently.

The Christian church father Augustinus of Hippo (lived 354 – 430 CE) apparently knew at least some Punic and found it sufficiently similar to Hebrew to assist in his exegesis of certain passages from the Hebrew Bible.