The tongue in speech and feeding: Comparative articulatory modelling Antoine Serrurier a,n , Pierre Badin b , Anna Barney a , Louis-Jean Bo ¨ e b , Christophe Savariaux b a Institute of Sound and Vibration Research, University of Southampton, Southampton, UK b GIPSA-Lab (De ´partement Parole & Cognition/ICP), UMR 5216 CNRS—Grenoble INP, Universite´ Stendhal, Universite´ Joseph Fourier, France article info Article history: Received 22 April 2011 Received in revised form 3 August 2012 Accepted 8 August 2012 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. & 2012 Elsevier Ltd. All rights reserved. 1. Introduction Of all living species, human beings are the only ones that communicate through speech. The origin of speech, however, still remains largely unexplained although a large number of studies have been devoted to the evolution of speech production in humans (see e.g. MacNeilage (2008) for a review). Three main functions can be ascribed to the human vocal tract: breathing, feeding and speaking. Whilst breathing does not require complex vocal tract articulation, the tasks of feeding and speaking are associated with more involved articulatory movements requir- ing significant coordination. Noting that both ontogenetically and phylogenetically feeding tasks precede speaking tasks, MacNeilage (1998) suggests in his paper on the frame/content theory of the evolution of speech production, that the ‘‘articulatory cyclicity of speech evolves from ingestive cyclicities’’. He describes speech as open–close mandibular alternations, which start at babbling onset, and whose cyclicity may have evolved from jaw cyclicity in feeding. Note, however, that this theory has been subject to debate and alternative origins have been proposed for the articulatory cyclicity of the jaw, such as call vocalisation (e.g. Andrew, 1998 or J¨ urgens, 1998) or modulation of acoustic parameters (Ohala, 1998) for example. Following MacNeilage’s theory and noting furthermore that feeding is a more fundamental activity than speech, Hiiemae et al. (2002) and Hiiemae and Palmer (2003) hypothesize that the tongue movements during speech may be ‘‘derived from the wide variety of tongue movements found in suckling and feeding’’. Generalising this hypothesis, they explicitly suggest in their paper that the movements of speech might be a subset of those used in feeding (Hiiemae & Palmer, 2003). Within this context, we present in this paper a first compara- tive modelling articulatory study of the movements of the tongue in speech and feeding. Our research aims to provide an original methodological framework to tackle this question from an articu- latory modelling point of view. As detailed later, the articulator movements are characterised by way of articulatory modelling of the vocal tract for each task under study, i.e. speech and feeding. Note that this paper is a greatly expanded version of Serrurier, Barney, Badin, Bo ¨ e, and Savariaux (2008). Note also that the question of the motor control system in speech vs. feeding and its implication for evolution will decidedly not be considered in this study. To set the scene for our study we summarise for the reader in the next two sections the movements of the vocal tract in speech and feeding and review the literature dedicated to the compar- ison between these movements. The following section is dedi- cated to the various measurement techniques adopted in feeding Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/phonetics Journal of Phonetics 0095-4470/$ - see front matter & 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.wocn.2012.08.001 n Corresponding author. Presently at: Laboratoire Traitement et Communication de l’Information (LTCI), UMR 5141 CNRS—Institut Te ´le ´ com, Te ´le ´ com ParisTech, 75013 Paris, France. Tel.: þ33 145818304. E-mail addresses: Antoine.Serrurier@ensam.eu (A. Serrurier), Pierre.Badin@gipsa-lab.grenoble-inp.fr (P. Badin), ab3@soton.ac.uk (A. Barney). Journal of Phonetics 40 (2012) 745–763