Phonetic and Other Influences on Voicing Contrasts

What factors influence how languages use voicing and aspiration? Some influences are phonetic: a salient auditory boundary between short and long lag VOT values favors the perception of aspiration contrasts, while a clear gestural distinction favors the production of voicing contrasts. But even within a language, speakers differ in how they produce contrasts. Examination of speaker variation in English suggests that some speakers value uniformity of articulation and/or acoustics over articulatory ease, while others value ease of articulation over acoustic uniformity, even though it results in acoustic alternations. Other examples in the literature show that phonetic factors such as auditory salience and ease of articulation interact with another non-phonetic factor, symmetry. Thus it seems that uniformity, i.e. consistency in phonetic form and avoiding allophony, and symmetry, i.e. the uniform or parallel behavior of members of a class, are as important in shaping sound systems as are phonetic factors.