“…The data presented in the classification matrices (Tables 2 and 3) and the distance matrix (Table 4) for vowels indicated that /
/, /
/, /
/, and /
/ were easier to distinguish than were /
/, /
/, /
/, and /
/. This result supports the previous findings that low tongue vowels (e.g., /
/) have more articulatory variation than high tongue vowels (e.g., /
/ and /
/, see Perkell & Cohen, 1989; Wang, Green, Samal, & Carrell, 2010). More specifically, our results suggest high and front vowels (i.e., /
/, /
/, /
/, and /
/) are more articulatory distinct than low and back vowels (i.e., /
/, /
/, /
/, and /
/).…”