[2] This unitary scheme was criticized by, among others, Alois Walde, Vittore Pisani and Giacomo Devoto, who proposed a classification of the Italic languages into two distinct Indo-European branches.

[3] Proponents such as Rix later rejected the idea, and the unitary theory (proposing the descent of all Italic languages from a unique common ancestor) remains dominant.

[4] In any case, it is plausible that the spread of all those languages took place through progressive inflows of Indo-European populations of eastern origin, with Osci and Umbri reaching the Italian peninsula after Latins and Falisci, but before Iapygians and Messapians.

These languages were spoken in Samnium and in Campania, partly in Apulia, Lucania and Bruttium, as well as by the Mamertines in the Sicilian colony of Messana (Messina).

Sabellic was originally the collective ethnonym of the Italic people who inhabited central and southern Italy at the time of Roman expansion.

Although the Osco-Umbrian languages are far more poorly attested than Latin, a corpus of a few thousand words' worth of inscriptions has allowed linguists to deduce some cladistic innovations and retentions.