This chapter examines the language of Lucilius’ hexametrical satires, discussing aspects of vocabulary, morphology, syntax and versification. The varied typology of Lucilius’ supposedly early lexicon (obsolete words; words tied to genre, whether high-style or comic; evidence of seemingly spoken usage in various registers) demonstrates that whatever characteristics of earlier diction Lucilius retains are largely motivated by literary purposes, and often innovated upon. Morphological and syntactical features which Classical Latin will discard are also few and coexisting with diachronic or diastratic variants. Pronounced alliteration, synonymic pairs, and persistent reduction of final -s place firmly Lucilius in pre-neoteric poetic diction - but this too is stylised, marked language. The answer to the question ‘How early Latin is Lucilius?’ is, not very much, if we are looking for evidence of a superseded variety of Latin rather than deliberate literary choices for the sake of register, style or genre.