The tongue in speech and feeding: Comparative articulatory modelling

Abstract

Two major functions of the human vocal tract are feeding and speaking. As, ontogenetically and phylogenetically, feeding tasks precede speaking tasks, it has been hypothesised that the skilled movements of the orofacial articulators specific to speech may have evolved from feeding functions. Our study explores this hypothesis by proposing an original methodological approach. Vocal tract articulatory measurements on two male subjects have been recorded for speech and feeding by electromagnetic articulography. Two guided Principal Component Analysis (PCA) articulatory models of the jaw/tongue system have been built for speech and feeding tasks. The two articulatory models show similar reconstruction accuracy. The speech and feeding articulations have been reconstructed respectively from feeding and speech raw PCA models. Root mean square reconstruction errors show better capacity of the feeding model to be generalised to the other set of articulations than the speech model. Our study suggests therefore that the tested hypothesis cannot be excluded on articulatory grounds for our two cases and brings a new methodology into the discussion of the ontogenetic and phylogenetic origins of speech.