Lenition of fricative sibilants in casual conversations in Basque

This paper analyses lenition of lamino-alveolar and apico-alveolar fricative sibilants in Basque in casual conversations between speakers of the variety of Beasain (Central Basque dialect). To describe the phonetic realisation of sibilants, the following measures were used: the proportion of voiced frames, the centre of gravity and relative intensity. Results show that 13% of sibilants can be classified as ‘voiced’ (i.e. they show uninterrupted voicing during the middle 50% of the duration) and another 25% has at least one voiced frame in the middle interval. Several factors were identified as important predictors of voicing: context, speech rate and the presence of the word boundary. It is also shown that voicing lowers the sibilants’ centre of gravity and relative intensity. Finally, the paper discusses potential lexical effects in lenition phenomena.