# More on Sibilant Devoicing in Spanish Diachrony: An Initial Phonetic Approach
## 2 The Acoustic Approach
### Results
#### 2.2.3 Cross-Category Comparison  
An overall comparison among all the categories has been carried out for both duration and fraction of unvoiced frames (sibulant and dialect as fixed effects, speaker and word as random variables). The model reveals a significant effect of the sibulant on duration (F(7, 9) = 51.970, \(p<0.0001\)) and on fraction of unvoiced frames (F(7, 9) = 82.209, \(p<0.0001\)). Dialect does not affect these parameters. In all cases, the speaker conditions the results (se = 38.033, \(Z=2.234\), \(p<0.025\), and se = 36.127, \(Z=2.321\), \(p<0.020\)). Interaction of the two factors has been found for the two dependent variables (F(7, 473) = 2.771, \(p<0.008\), and F(7, 473) = 6.640, \(p<0.0001\)). As for the fixed effects, both duration and fraction of unvoiced frames distinguish all the categories13 except in a few cases. [s] displays similar duration to the fricative siblants, [] is equivalent to [d\(\overline{\text{s}}\)] and [\(\overline{\text{s}}\)] is also similar to [\(\overline{\text{t}}\)]. Regarding the fraction of unvoiced frames, [z] shows no significant difference from [\(\overline{\text{s}}\)] and [d\(\overline{\text{s}}\)], nor do [s] from [] and [\(\overline{\text{t}}\)] from [] and [\(\overline{\text{t}}\)]. In the remaining cases, voiceless counterparts have significantly longer duration and higher rates of unvoiced frames. It is worth noting that, while there is no overlap between voiced and voiceless segments if we consider fraction of unvoiced frames, there is a degree of overlap if we use duration as the criterion. Footnote 13: [[https://www.math.ucsd.edu/~marc/](https://www.math.ucsd.edu/~marc/)]([https://www.math.ucsd.edu/~marc/](https://www.math.ucsd.edu/~marc/))  
At this point, if [PERSON]'s (1997, p. 478) classification of the degree of voicing is applied, overlapping seems to be general across categories in the intermediate range (see Table 6, Figure 2). In fact, almost all the categories present fully voiced utterances, fully devoiced ones and, more importantly for our purposes, partially devoiced realizations. Only alveolar fricatives and voiceless alveopalatals tend to be clearly realized at the extremes (fully voiced or fully devoiced), instances of the other categories being concentrated in an intermediate range from 11% to 75% of unvoiced frames. This still holds true when examined by dialect, apart from [] in Majorcan Catalan. Figure 2: Bar plots showing the distribution of the three variants in [PERSON] (1997) for each phonological category in Girona Central Catalan and in Majorcan Catalan. Statistical analysis confirms these observations. The model indicates that the sibilant category (F(14, 12) = 2.957, \(p<0.033\)) and the interaction between category and dialect (F(14, 479) = 2.523, \(p<0.002\)) have an effect on the degree of voicing. Fully devoiced variants are significantly more frequent in [s] (b\({}_{0}\) = 5.321, see = 1.603, t = 3.319, \(p<0.001\)), [] (b\({}_{0}\) = 5.078, se = 1.601, t = 3.171, \(p<0.002\)) and even [fs] (b\({}_{0}\) = 4.244, se = 1.609, t = 3.558, \(p<0.002\)), while partially devoiced variants are significantly more common in [d\(\widehat{s}\)] (b\({}_{0}\) = 2.222, se = 0.625, t = 3.319, \(p<0.001\)). On the other hand, partially devoiced cases are significantly less common than expected in [z] (b\({}_{0}\) = \(-\)3.091, se = 0.759, t = \(-\)4.072, \(p<0.001\)) and, at the limit of significance, [s] (b\({}_{0}\) = \(-\)1.621, se = 0.742, t = \(-\)2.184, \(p<0.049\)). As commented, dialect as a main effect is not relevant, but if we break down the effect, Majorcan Catalan seems to display fewer partially devoiced realizations than Girona Central Catalan (b\({}_{0}\) = \(-\)2.225, se = 0.732, t = \(-\)3.038, \(p<0.003\)). However, Majorcan Catalan [z] is more prone to partially devoiced variants than Girona Central Catalan (b\({}_{0}\) = 2.762, se = 0.907, t = 3.047, \(p<0.002\)): the average of this kind of realizations, in fact, is significantly higher (33.3% vs. 27.5%).