Is simple language a feature of political populism? Language can divide society into ‘elite’ and ‘popular’ classes. Populist politicians have ideological and electoral incentives to exploit this division by simplifying their communication style. This study (1) develops and validates a novel dictionary of political populism; (2) applies this dictionary to a corpus of 78,855 utterances from the most recent Italian parliament to estimate the relationship between populist term usage and language complexity at the individual and party levels; and (3) observes whether a change in allegiance from a populist to a mainstream parliamentary group increases a lawmaker's plenary spoken language complexity. Our results suggest that populist ideology, both at the individual and party levels, influences how lawmakers shape their communication style.