
The aim of this paper is to show a complete overview of the representation of the three couples of sibilant sounds represented in the documentation in relation to the devoicing process based on a research made on 510 texts from the files in the Cathedral of Lleón, written between 1188 and 1284 in the notaries from the South of the Cantabrian Mountain Rage, specially those written in the area of influence of the cathedral and he primitive council of Lleón. The survey with the aim of lightening this theme, really discussed between linguists, is specially centred on the problem of graphic alternations that could be the starting point for the devoicing process of sibilant sounds.
Historical linguistics, voiceless sibilants, voiced sibilants, Astur romance, 12th-13th Centuries.