A study of voicing and context effects upon consonant linguapalatal contact patterns

Consonant linguapalatal contacts were studied using electropalatography (EPG) by recording 10 normal, English-speaking adults repeating CV syllables (C = /t,d,k,g,s,z,∫,3,t∫,d3,r,l/, V = /i,a,u/). Contact patterns were examined for total number of electrodes contacted and for consonant specific parameters. Comparisons were made across vowel environments and voicing contrasts. For alveolar and velar stops, the voiced cognates had greater anterior/posterior (A/P) midline lengths of contact while lateral contacts remained relatively the same. This suggested lateral tongue contact was primarily used for creating a seal to prevent air escape while the central regions responded to the voicing differences. Vowel anticipatory effects resulted in the greatest number of contacts in the /i/ context and the fewest in the /a/ context. For the sibilants, groove widths were dictated by voicing characteristics (narrower for voiced cognates) and the grooves were unaffected by vowel context. Vowel context effects were seen for lateral widths of contact only. Vowel context effects were found to affect both length and width of contact for the /r/ whereas with the /1/ only the lateral A/P lengths of contact were affected. Results are discussed in terms of physiological constraints upon the tongue in producing the various consonants, the three dimensional nature of the tongue, and the ability of the tongue components (e.g., tip, blade, dorsum) to function relatively independently.