In this paper we report an experiment of accentual
placement in Errenteria Basque. We compare data from
three generations of speakers with the data described in
previous literature. The results show a mixed accentual
system with marked and unmarked words (as previously
addressed in the literature). The relevant fact is that the
phonological shape of the current unmarked words is
different from the descriptions in the literature since the
current one is a stress-accent system and the previous one suggests to be a pitch-accent system. Based on diachronic data, we show the direction of the phonological change and point a possible explanation for the development of the new accentual system based on Hualde's hypothesis.