Archaic Latin refers to the earliest attested stages of the Latin language, from its first surviving inscriptions around the sixth century BCE through roughly the second century BCE, before the grammatical and orthographic standardization that produced Classical Latin, the more familiar literary register of Cicero, Virgil and the late Republic and early Empire.
Archaic Latin belongs to the Italic branch of the Indo-European family, and its surviving evidence, including the Duenos inscription and the Lapis Niger, a fragmentary and much-debated inscription found in the Roman Forum thought to relate to early Roman religious or legal practice, offers rare direct textual access to Rome's earliest religious vocabulary and formulaic ritual language before later literary Latin smoothed over much of its archaic grammar.
Some of Rome's oldest religious institutions, including the Arval Brothers priestly college, preserved specifically archaic liturgical formulas in their ritual hymns and prayers long after the spoken language itself had moved on, treating linguistic conservatism as integral to a prayer's religious efficacy in a pattern comparable to Vedic Sanskrit's own preservation of archaic recitation forms within Hindu ritual.