# More on Sibilant Devoicing in Spanish Diachrony: An Initial Phonetic Approach
## 5 Conclusions  
This paper is a first approach to sibilant devoicing in the history of Spanish, a process that concluded in the 16 th century. Since such a process has been deemed atypical, the usual explanations claimed that devoicing was the result of a reorganization of the mediaeval phonological system aiming at more symmetry and/or more efficiency. Other justifications invoked linguistic contact as the reason for the neutralization: pressure from Basque, which lacks voiced sibilants, could have induced voicing neutralization in Spanish. However, phonetic factors can explain the sound change in a more simple and efficient way, as [PERSON] (1993) or [PERSON] (1995, 1997) have pointed out.  
Following recent methods in historical linguistics, we turned to comparative grammar and experimental phonetics to examine the topic in greater depth and try to determine whether this evolution could be understood as a phonetically based sound change, initiated for internal reasons. With this purpose in mind, Catalan sibilants were acoustically and perceptually analysed in terms of consonant duration, intensity and fraction of unvoiced frames, also taking into account their degree of voicing.  
Our results point to a phonetically based sound change, since devoicing may be accounted for in terms of acoustic and aerodynamic factors, as well as in terms of misperception, like most regular sound changes. As has been pointed out, voiced sibilants are not common segments in the world's languages and tend to devoice due to aerodynamic constraints. This is evidenced by means of certain acoustic features, such as duration and fraction of unvoiced frames. If the cloud of exemplars of voiced sibilant categories overlaps with the cloud of exemplars of their voiceless counterparts, the voiceless options will be preferred, since their production is more efficient. Moreover, perceptual ambiguity among exemplars in the peripheral area in the acoustic-auditory space will pave the way for reanalysis and recategorization. This process will be favoured more if the phonological opposition has a low functional load, as was the case in Medieval Spanish sibilants.  
However, it is important to remark that our results are only tentative, since the sample in the acoustic experiment is clearly limited: more recordings are required in future research to guarantee solid findings. Even in the perception experiment more participants should be recruited for further analysis in order to ensure more representative results. Moreover, it will be crucial to refine the corpus, to achieve a more solid analysis of voiceless dentoalveolar affricates and more reliable comparison between the sibilants. Taking these aspects into account will be the way to obtain more substantial results to support these preliminary findings.  
This research received no external funding.  
Ethical review and approval were waived for this study, since the data is properly anonymized and informed consent is obtained at the time of original data collection.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
Data Availability Statement: Data available on request due to restrictions in privacy in the informed consent signed by the speakers. The data presented in this study are available on request from the corresponding author. The data are not publicly available due to the mentioned restrictions in privacy, which prevents the authors to publicly share the obtained data with third parties.  
This work would not have been possible without the generous help and interesting observations from [PERSON] and [PERSON]. I would also like to thank three anonymous reviewers for their helpful comments.  
The author declares no conflict of interest.