The Proto-Italic language is the ancestor of the Italic languages, most notably Latin and its descendants, the Romance languages. It is not directly attested in writing, but has been reconstructed to some degree through the comparative method. Proto-Italic descended from the earlier Proto-Indo-European language.

Although an equation between archeological and linguistic evidence cannot be established with certainty, the Proto-Italic language is generally associated with the Terramare (1700–1150 BC) and Proto-Villanovan cultures (1200–900 BC).

On the other hand, work in glottochronology has argued that Proto-Italic split off from the western Proto-Indo-European dialects some time before 2500 BC. It was originally spoken by Italic tribes north of the Alps before they moved south into the Italian Peninsula during the second half of the 2nd millennium BC. Linguistic evidence also points to early contacts with Celtic tribes and Proto-Germanic speakers.

A list of regular phonetic changes from Proto-Indo-European to Proto-Italic follows. Because Latin is the only well-attested Italic language, it forms the main source for the reconstruction of Proto-Italic. It is therefore not always clear whether certain changes apply to all of Italic (a pre-PI change), or only to Latin (a post-PI change), because of lack of conclusive evidence.

The laryngeals are a class of hypothetical PIE sounds *h₁, *h₂, *h₃ that usually disappeared in late PIE, leaving coloring effects on adjacent vowels. Their disappearance left some distinctive sound combinations in Proto-Italic. In the changes below, the # follows standard practice in denoting a word boundary; that is, # at the beginning denotes word-initial. H denotes any of the three laryngeals.

The simpler Italic developments of laryngeals are shared by many other Indo-European branches:

More characteristic of Italic are the interactions of laryngeals with sonorant consonants. Here, R represents a sonorant, and C a consonant.

Proto-Italic had the following diphthongs: