An evaluation of several methods for computing lingual coarticulatory resistance using ultrasound

The paper evaluates the efficiency of six computation methods in distinguishing lingual coarticulatory resistance among consonants and vowels using ultrasound data. This research goal is tested on a corpus of symmetrical vowel-consonant-vowel sequences composed of 10 consonants and five vowels produced by five Catalan speakers. Results show that, while the coarticulatory resistance hierarchies obtained by all methods conform largely to the predictions of the degree of articulatory constraint model of coarticulation, some (i.e., area of the articulatory zone, mean point-by-point coefficient of variation, and mean nearest neighbour distance) are somewhat more highly predictive than others (i.e., locus equation, mutual information, and highest point of the tongue dorsum). Methods differ mostly regarding the classification of consonants exhibiting intermediate degrees of coarticulatory resistance due to the way the methods have been designed. The implications of these findings for research on dialectal variation are discussed.