Labial softening

This chapter is about the palatalization and assibilation of labial and nasal stops, and of labiodental fricatives. Based on several diachronic pathways, it presents the hypothesis that labial softening is achived through glide fricativization or occlusivization, depending on the language or dialect taken into consideration. A special analysis is performed of labial palatalization and assibilation in the Bantu languages, Romanian dialects, and /Cl/ onset clusters in Romance, where those changes may have taken place once the alveolar lateral shifted to a palatal approximant. In so far as two independent articulators, i.e., lips and tongue, are involved in the production of the labial and labiodental sequences of interest, their diachronic development turns out to be far more complex than the palatalization and softening of velar and dentoalveolar obstruents.

Conclusion

The Discussion chapter summarizes the main findings of the book regarding those contextual, positional, and prosodic conditions which trigger velar and labial softening, and the acoustic cues which are responsible for the integration of (alveolo)palatal stops as affricates differing in place of articulation. The arguments in support of an articulation-based interpretation of these sound changes are also summarized and evaluated. The chapter also addresses some phonological issues, namely, why (alveolo)palatal stops are phonetically but not phonologically frequent, and the extent to which their realization is conditioned by the number of dorsal-stop phonemes in the language.

Velar palatalization

An analysis of the conversion of velar stops before front vocalic segments, and in other contextual and positional conditions, into plain palatal, alveolopalatal, and even alveolar articulations is carried out using descriptive data from a considerable number of languages. Articulatory data on (alveolo)palatal stops reveal that these consonants are mostly alveolopalatal in the world’s languages, and also that their closure location may be highly variable, which accounts for their identification as /t/ or /k/. It is claimed that velar palatalization may be triggered by articulatory strengthening through an increase in tongue-to-palate contact in non-front vocalic environments.

Velar assibilation

Lingual affricates differing in place of articulation, i.e., mostly [tʃ] but also [ts] and other affricates, may emerge naturally from the (alveolo)palatal stop outcome of velar palatalization. This is strongly suggested by the co-occurrence of (alveolo)palatal stops and one of the lingual affricates in specific dialectal domains, and by the existence of languages where velar softening has yielded either [tʃ] ot [ts] but not both, presumably owing to dialect-dependent differences in base of articulation. Specific spectral, duration, and intensity characteristics render the (alveolo)palatal stop burst comparable to the frication noise of a front lingual affricate, and the affrication process is likely to operate in those positional, contextual, and prosodic conditions which favour the presence of one or more of these acoustic properties. The affinity between the assibilation of velars and dentoalveolars is also subject to investigation.

Velar softening

In so far as velar softening is a two-stage process involving velar palatalization and velar assibilation, it is claimed that these two sound-change mechanisms ought to be analysed separately. A distinction is made between front velar stop productions, and the (alveolo)palatal stop outcome of gestural blending between velar stops and front vocalic realizations. The chapter also presents and evaluates two general models of velar softening, i.e., the articulation-based model proposed by the Neogrammarians and the acoustic equivalence model proposed by Ohala and colleagues. Several arguments in support of the former model are presented, which are based on articulatory evidence and on experimental findings reported in earlier acoustico-perceptual studies.

Introduction

The chapter deals with the origin and phonetic causes of sound changes involving consonants, with the diachronic pathways connecting the input and output phonetic forms, and with models of sound change (e.g., Evolutionary Phonology, the Neogrammarian’s articulatory model, Ohala’s acoustic equivalence model). The need to use articulatory and acoustic data for ascertaining the causes of sound change (and in particular the palatalization and assibilation of velar, labial, and dentoalveolar obstruents) is emphasized. The chapter is also concerned with how allophones are phonologized in sound-change processes and with the special status of (alveolo)palatal stops regarding allophonic phonologization.