Abstract: (Duendes and Spiriduși: dousehold deities in lower mythologies, a linguistic and folkloric study)The present research proposes a comparative, diachronic analysis of two household deities, the Spanish duende, and the Romanian spiriduș, using conceptual instruments of both linguistic and folklore studies. These spirits register a marked presence in folklore, in fairy tales and in the popular belief system, even in what concerns their representation, behaviour, effects on people, and adjacent rituals. Their linguistic evolutions differ, visible through the fact that the duende has a vaster documented historical presence. Its earliest-known occurrences date back to eleventh-century sources. During the fifteenth century, the duende gathered the meaning of housebound spirit, and later, in early modern treatises on witchcraft, demonology and exorcisms, became the subject of intense debate. In contrast to the duende's vast textual documentation, the spiriduș has a more timid representation, most visible in ethnographic studies dating from the 1800s, but nevertheless having deep social roots. I argue that the two can be considered members of the same category, given their shared traits and the wider mythological context. The main arguments refer to their origin in ‘lower’ mythologies, as postulated by Wilhelm Mannhardt, and to the shared aspects that distinguish them from household deities in ‘higher’ mythologies, such as the Roman lares. I also aim to analyse the presence of folklore in language and how people’s attitudes towards it become visible through the words spoken, by way of popular sayings and incantations, functioning as a manner of folk-magic.