Proto-Isaiah is a name associated with the authorship of the first part of the Book of Isaiah in the Hebrew Bible.

The proto-priest led the ceremony.

Proto-Afrasian is a name that is synonymous with Proto-Afroasiatic.

Proto-Afrasian languages are believed to be the ancestral language of the Afroasiatic language family.

Proto-Hlai is the reconstructed ancestor of the Hlai languages.

Proto-Tocharian is an ancient Indo-European language.

Proto-Nuristani is an ancient language spoken in the Nuristan region of Afghanistan.

Proto-Inuit is an ancient language that preceded the Inuit languages.

The proto-Slavic language is the common ancestor of all Slavic languages.

Proto-prog is a subgenre of progressive rock.